Name: synthesis of cyclic polymers and characterization of their diffusive motion in the melt state at the single molecule level
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This work was supported by a Grant-in-Aid for Scientific Research No. 22750122 (S.H.), No. 26288099 (T.Y.), and No. 23350050 (Y.T.) of the Japan Society for the Promotion of Science. S.H. is grateful for The Kurata Memorial Hitachi Science and Technology Foundation. The research reported in this publication was supported by the King Abdullah University of Science and Technology (S.H.).

Tek fonksiyonlu ve iki fonksiyonlu Poli 1. N- (THF) <ol><li> Tek fonksiyonlu poli (THF) <ol><li> Alev 2 boyunlu 100 ml&#39;lik yuvarlak tabanlı bir şişeye kuru. Vakum ve nitrojen (3 kür) ile şişeyi doldurun. </li><li> şişeye damıtılmış tetrahidrofuran (THF) (50 mi) eklenir. 20 ° C&#39;de bir su banyosu içinde balon koyun ve sıcaklık dengelenmesi. </li><li> Bir şırınga ile bir şişeye metil triflat (0.5 mmol) ekleyin. 20 ° C&#39;de 5-10 dakika süreyle karıştırın. </li><li> Bir şırınga ile bir şişeye N-fenil pirolidin (4-6 eşi.) Eklenir. 30-60 dakika boyunca karıştırın. </li><li> Tamamen düşük basınçta (yaklaşık 100 Torr) altında çözücüyü çıkarın. aseton 3-5 ml artığı içinde çözündürülür. N-heksan 300-500 ml aseton solüsyonu ekleyin. çökelti filtre edin ve indirgenmiş basınç altında kurutulur. </li></ol></li><li> Çift işlevli poli (THF) <ol><li> Alev 2 boyunlu 100 ml&#39;lik yuvarlak tabanlı bir şişeye kuru. Vacuum ve azot (3 kez) ile şişesi doldurun. </li><li> şişeye damıtılmış THF (50 mi) eklenir. 20 ° C&#39;de bir su banyosu içinde balon koyun ve sıcaklık dengelenmesi. </li><li> Bir şırınga ile şişeye triflik anhidrit (0.3 mmol) ekleyin. 20 ° C&#39;de 5-10 dakika süreyle karıştırın. </li><li> Bir şırınga ile bir şişeye N-fenil pirolidin (4-6 eşi.) Eklenir. 30-60 dakika boyunca karıştırın. </li><li> Tamamen düşük basınçta (yaklaşık 100 Torr) altında çözücüyü çıkarın. aseton 3-5 ml artığı içinde çözündürülür. N-heksan 300-500 ml aseton solüsyonu ekleyin. çökelti filtre edin ve indirgenmiş basınç altında kurutulur. </li></ol></li></ol> 2. Perylene Sentezi etitkarbodiimit-dahil 4 kollu yıldız ve 8 şeklinde disiklik Poli (THF) <ol><li> Silahlı yıldız poli (THF) <ol><li> İyon değişimi <ol><li> Suda perilen diimid tetrakarboksilat, sodyum tuzu (10 mg / ml, 150 mi) içinde çözülür. eritmekAseton tek fonksiyonlu poli (THF) (160 mg / ml, 4 mi) eklenmiştir. kuvvetli bir şekilde karıştırıldı, sulu çözelti içine aseton çözeltisi damla damla ekleyin. süzme ile oluşan çökeltiyi toplamak. </li><li> kazanılan çökelti (2.1.1.1) dört kez yukarıdaki işlemi tekrarlayın. </li></ol></li><li> kovalent tespit <ol><li> toluen içinde elde edilen çökelti (5 mg / ml) içinde çözülür. 4 saat çözelti, geri akış. </li><li> Tamamen düşük basınçta (yaklaşık 100 Torr) altında çözücüyü çıkarın. N-heksan / aseton (2/1 hacim / hacim), bir silika jel tıpası içinden tortu filtre. Ürünü çöktürmek için buz gibi soğuk su (300-500 ml) içine çözeltisi ekleyin. Çökeltinin süzülerek toplanır. </li></ol></li></ol></li><li> Disiklik 8-şeklinde bir poli (THF) <ol><li> İyon değişimi <ol><li> Suda perilen diimid tetrakarboksilat, sodyum tuzu (6 mg / ml, 50 mi) içinde çözülür. (0.5 g çift fonksiyonlu poli (THF) içinde çözülür) Aseton 30-50 ml. 0 ° C&#39;de kuvvetli bir şekilde karıştırıldı, sulu çözelti içine aseton çözeltisi damla damla ekleyin. süzme ile oluşan çökeltiyi toplamak. </li><li> kazanılan çökelti (2.2.1.1) ile yukarıdaki işlemi tekrarlayın. </li></ol></li><li> kovalent tespit <ol><li> toluen içinde elde edilen çökelti (0,05 g / L) içinde çözülür. 4 saat çözelti, geri akış. </li><li> Tamamen düşük basınçta (yaklaşık 100 Torr) altında çözücüyü çıkarın. Kısmen tortu çözünmesi için toluen ekleyin. Yeniden çökeltilmesi n-heksan 300-500 ml. </li><li> N-heksan / aseton (2/1 hacim / hacim), bir silika jel tamponundan oluşan çökelti filtre. Yeniden çökeltilmesi su 300-500 ml. </li><li> Bir polistiren jel kullanılarak kolon kromatografisiyle 18 ile oluşturulan çökelti saflaştınlır. Bundan başka REM CHCI3 bir eluent ile 19 preparatif jel geçirgenlik kromatografisi (GPC) ile ham ürünün arıtılmasırefraktif indeks (RI) ve UV dedektörler izleyerek ove yan. </li></ol></li></ol></li></ol> 3. Tek-molekül Floresans Görüntüleme Deneyi <ol><li> örnek hazırlama <ol><li> Mikroskop kapak fişleri temizliği <ol><li> Yeri No 1.5 24 x 24 mm mikroskop kapağı boyama kavanoza kayıyor. </li><li> 15 dakika boyunca kavanoz ve sonikasyon olarak 1 M potasyum hidrit çözeltisi (100 mi) eklenir. durultma yoluyla potasyum hidroksit çözeltisi dökün ve birkaç kez ultra saf su ile kapak slipi üzerinde çalkalayın. 15 dakika boyunca kavanoz ve sonikasyon içine spektroskopik dereceli etanol (100 mi) eklenir. </li><li> durultma yoluyla etanol dökün ve birkaç kez ultra saf su ile kapak fişleri durulayın. durultma yoluyla ultra saf su kapalı döküldükten sonra, adımı 3.1.1.2 tekrarlayın. </li><li> 15 dakika boyunca kavanoz ve sonikasyon ultra saf su ekleyin. birkaç kez ultra saf su ile kapak fişleri durulayın. Bir plastik cımbız ile kavanoz kapağı fişleri çıkarın ve kuru hava veya kuru nitrojen ya onları kurutun. </li></ol></li><li> Polimer eriyiği örnekleri 14,15 hazırlanması <ol><li> bir cam şişe içinde etiketli olmayan lineer poli (THF) 100 ul ilave edin ve bir saç kurutma makinesi kullanılarak erime noktasından (yaklaşık 25 ° C) üzerindeki bir sıcaklığa kadar ısıtılır. </li><li> Florofor dahil polimer (lineer, 4 kollu bir yıldız, siklik ya da 8-şeklinde bir disiklik 2.1 ve 2.2 sentezlenir), kloroform (1 mi, 10 -6 M) içinde çözülür. etiketli olmayan lineer poli (THF) eriyiğin 100 ul çözelti 1 ul ekle. </li><li> İyice bir pipet ucu ile karıştırılarak sonra, kurutucu kullanılarak örnek ısıtılmasıyla kloroform buharlaşır. NOT: Bu florofor dahil polimerlerin 10 8 M ihtiva eden etiketli olmayan lineer poli (THF) içindeki bir eriyiği içerir. </li><li> örnek 10 ul mikro-pipet ve D&#39;nin kullanımı almakbir temizlenmiş kapak kayma üzerinde ROP. numune üzerinde başka temizlenmiş kapak kayma koyun ve iki kapak fişleri arasında örnek sandviç. </li><li> nazikçe plastik cımbız kullanarak örnek basınız. </li></ol></li></ol></li><li> Geniş alan floresan görüntüleme kurulumu 15 <ol><li> Ters mikroskop arka portuna bir uyarım lazer (488 nm) tanıtımı <ol><li> ışın yoluna bir uyarım bant geçiren filtre ve polarize takın. </li><li> Bir ışın genişletici tarafından çapı yaklaşık 1 cm ışını genişletin. </li><li> ışın yoluna çeyrek dalga plakası yerleştirin. polarizörün olduğu ile ilgili olarak 45 derece dalga plakası optik eksenine ayarlayın. Alternatif olarak, bir Berek kompansatör eklemek için / 4 l optik gecikmeyi ayarlamak. </li><li> kiriş boyutunu ayarlamak için uyarma ışın yolunda bir diyafram takın. </li><li> ters optik mikroskobik arka portuna lazer ışını tanıtan öncePE, bir odaklama lensi yerleştirin (Plan dışbükey lens, odak uzaklığı ≈ 300 mm) objektif lens üzerinden bir lazer ışını kolime olan bir pozisyonda. </li></ol></li><li> Bir filtre küpü üzerine monte edilmiş bir dikroik ayna kullanılarak lazer ışını yansıtılarak ve sonra yüksek bir sayısal açıklık (NA) objektif lens numuneye lazer ışını tanıtmak (örneğin NA 1.3, 100X büyütme, yağ daldırma). </li><li> objektife objektif bir ısıtıcı takın ve 30 ° C sıcaklığını ayarlamak. </li><li> Ters mikroskop aşamasında numune montaj <ol><li> objektif lens üzerinde immersiyon bir damla damla ve mikroskop durumuna örnek monte edin. </li><li> yaklaşık 10 um örnek kalınlığı numunenin alt ve üst yüzeyi eksenel pozisyonunu kontrol edilmesiyle elde olduğundan emin olun. </li><li> numunenin alt yüzeyi üzerinde bir kaç mikrometre mikroskop odağı ayarlayın. </li></ol></li&gt; <li> Objektif mercek altında dairesel polarize uyarma ışık elde <ol><li> objektif lens dışarı paralelleştirilmiş lazer ışınına bir polarize yerleştirin. </li><li> polarize sonra bir güç ölçer takarak polarize iletilen lazer yoğunluğunu kaydedin. polarize çevirerek farklı polarizasyon açılarında iletilen lazer gücünü kaydedin. </li><li> iletilen lazer gücü tüm polarizasyon açılarında sabit değilse, biraz uyarma ışın yoluna yerleştirilen çeyrek dalga plakası veya Berek kompansatör döndürün. </li><li> sabit iletilen lazer gücü kadar adımı yineleyin 3.2.5.2 ve 3.2.5.3 tüm polarizasyon açılarında elde edilir. dairesel polarize ışık numunesi elde emin olun. </li></ol></li><li> Kurulum EM (elektron çoğaltan) cihazı birleştiğinde -Ödeme (CCD) kamera <ol><li> mikroskop yan port EM-CCD kamera takın ve t bağlayıngörüntü elde etme yazılımı o. </li><li> Gerekirse, cihazlara EM-CCD kamera tarafından oluşturulan transistör-transistör mantığı (TTL) sinyalleri göndererek bir mekanik obtüratör veya uyarma ışın yolu takılı acousto-optik ayarlanabilir filtre kamera poz senkronize. Alternatif olarak, lazer EM-CCD kamera tarafından oluşturulan TTL sinyaller göndererek lazer çıkışına kamera poz senkronize. NOT:, çıkış gücü giriş transistörü-Transistör modüle edilebilir katı-hal lazer (TTL) sinyalleri deney için kullanılan yalnızca sonuncu seçenek, uygulanabilir. </li><li> Tek fluorofor yüksek kalitede floresan görüntü elde etmek için kamerayı kontrol yazılımı kullanarak CCD kamera bir EM kazanç (genellikle yaklaşık 300) uygulayın. </li><li> Faiz (ROI) bir bölge kamerayı kontrol yazılımı kullanarak (görüş alanının merkezinde tipik 128 x 128 piksel) olarak ayarlayın. NOT: Bu IMAGI sağlareriyik numunedeki fluorofor dahil polimer zincirleri hareketini görüntülenmesi için gerekli olan çerçeve aktarım modunda, 200 Hz - 100 kare hızında ng deneyler. </li></ol></li></ol></li><li> deneme çalıştırırken <ol><li> Deneysel koşulları optimize <ol><li> uyarma ışın yolu takılı diyafram kullanarak çapı yaklaşık 20 um numunenin aydınlatma alanını ayarlayın. </li><li> elle uyarma ışın yoluna yerleştirilen uygun bir nötr yoğunluk (ND) filtresi seçerek 8 mW - 4 numune uyarma lazer gücünü ayarlayın. NOT: - 2 kW cm -2 örnek de bu 1 ortalama lazer gücü sağlar. </li><li> 200 Hz - 100 kare hızlarında örnek rekor floresan görüntüler. Bireysel florofor dahil polimerlerden elde edilen floresans yoğunluğu çok düşükse, yavaş yavaş TH ile uyarım gücünü artırmaknumune yaklaşık 100 mW ulaşana kadar e ND filtre. </li><li> tek-molekül floresan görüntü kalitesi hala tatmin edici değilse, etiketli olmayan poli (THF) saf bir eriyik floresan görüntüleri kaydederek numunede floresan kirleri kontrol edin. Yüksek floresan arka plan görülmektedir durumda, farklı etiketli olmayan poli (THF) kullanın. </li><li> eriyik içinde florofor dahil polimerlerden elde floresan nokta yoğunluğu uzamsal olması (bu pasif hareket analizinde hatalara neden) izole etmek için çok yüksek ise, örnek kadar içeri florofor dahil polimer konsantrasyonunu azaltmak mekansal izole noktalar görülmektedir. </li><li> eriyik içinde florofor dahil polimerlerden elde floresan nokta yoğunluğu (bu görüntüleme deneyinde düşük verim neden olur) çok düşük ise, appropr kadar örnek florofor dahil polimer konsantrasyonunu arttırmakfloresan nokta iate yoğunluğu ulaşılır. </li><li> eriyik içinde fluorofor dahil polimerlerden elde edilen floresan görüntüleri bulanık ise, görüntüleme edinimi çerçeve oranlarını artırmak. NOT: Bu genellikle tipik olarak 64 x 64 piksel daha küçük bir yatırım getirisi gerektirir. </li></ol></li></ol></li><li> Görüntü edinme <ol><li> Deney koşulları optimize sonra örnek denge şartları ulaşır, böylece bir saat mikroskop sahnede monte örnek bırakın. </li><li> 200 Hz kare hızı - 100 eriyik halde fluorofor dahil polimerlerin 1000 floresan görüntü dizileri - 500 kaydediniz. varsayılan dosya biçimi TIFF değilse, TIFF formatında tüm resim dizilerini dönüştürmek. </li></ol></li></ol> Pasif Hareket 4. Analizi <ol><li> Ortalama kare deplasman (MSD) analizi <ol><li> bu şekilde floresan görüntü dizilerini kırpmaHer görüntü sırası gibi ImageJ gibi tek ve iyi odaklanmış difüzyon fluorofor-dahil polimer kullanılarak görüntü işleme yazılımı içerdiğini. </li><li> kırpılan görüntü dizileri 10&#39;dan fazla kare içerdiğinde, her dizi 10 kare oluşur, öyle ki birçok dizinin içine resim dizileri ayrıldı. </li><li> doğru görüntü iki boyutlu Gauss geçme ile, her resim dizilerinin molekül konumlarını belirler. </li><li> Denklem 20 Difüzyon katsayısı (D), ayrı ayrı moleküllerin difüzyon yörüngeleri (molekül, yani zamana bağlı pozisyonları) ortalama-kare yer değiştirme (MSD) analizi ile belirlemek <img alt="Equation1" src="/files/ftp_upload/54503/54503equation1.jpg" /> x i ve y ı resim çerçevesi i molekülün pozisyonları ve n çerçeve i dan time lapse ¨ t çerçeve numarasını ifade etmektedir. </li><li> difüzyon katsayıları arsabir frekans histogramı. Not: Genellikle, histogram 100&#39;den moleküllerden yapılmıştır. </li></ol></li><li> Kümülatif dağılım fonksiyonu (CDF) analizi NOT: Bir CDF, P (r 2 i Δ t) i t ö belli bir zaman gecikmesi sonrası kökenli bir yarıçap r içinde difüzyon molekülleri bulmak kümülatif olasılık karşılık gelir. <ol><li> Zaman 4.1.3&#39;de elde edilen tüm difüzyon yörüngeleri için 1Δt, 2Δt, ····, iΔt arasında gecikme sırasında ortaya çıkan kareli-yer değiştirme hesaplayın. NOT: Saat iΔt ve gecikme için bu hesaplamalar toplam i karesi-yer değiştirmeleri m verir. </li><li> Farklı r 2 değerlerinde r 2 daha küçük olan toplam m i veri kümesi içinde karesi-değiştirmeler (l i) sayıları hesaplamak (0 &lt;r2 &lt;∞). R 2 vs normalize l i<html> araziler CDF, P (r 2, iΔt) karşılık gelmektedir. </li></ol></li><li> Tat difüzyon modelleri ile TDF analizi Not: Elde edilen CDFs farklı difüzyon modelleri ile donatılmıştır; Homojen difüzyon modeli, D dağılımı Gauss (tek Gauss modeli) tarafından tarif edildiği birden fazla difüzyon modları ve birden fazla difüzyon modları, D dağılımı çok Gauss (çoklu Gauss modeli) ile ifade edilir. <ol><li> Homojen difüzyon modelde, bir denklem 21 kullanılarak CDF takarak ortalama D belirlemek <img alt="Equation2" src="/files/ftp_upload/54503/54503equation2.jpg" /> NOT: denklemin herhangi bir sapma molekülünün heterojen difüzyon göstermektedir. </li><li> Tek Gauss modelde, 15 kullanılarak CDF uydurma bir Gauss (f (D)) tarafından açıklanan D olasılık dağılımını belirlemek On3 &quot;src =&quot; / files / ftp_upload / 54503 / 54503equation3.jpg &quot;/&gt; <img alt="Equation4" src="/files/ftp_upload/54503/54503equation4.jpg" /> A, W ve D 0 Gauss genlik, genişlik ve merkez olduğu. </li><li> Çift Gauss modelde, 14 kullanılarak CDF uydurma bir Gauss (f (D)) tarafından açıklanan D bileşeni inci j olasılık dağılımını belirlemek <img alt="Equation5" src="/files/ftp_upload/54503/54503equation5.jpg" /> <img alt="Equation6" src="/files/ftp_upload/54503/54503equation6.jpg" /> Bir j her bir difüzyon bileşen fraksiyonu ve α j, j B ve D 0 burada, j, Gauss bileşeni j nolu amplitüd, genişlik, ve merkez vardır. </li></ol></li><li> Teorik olasılık göre dağılımın hesaplanmasıDifüzyon katsayısı Katkı NOT: nedeniyle farklı difüzyon modelleri için hesaplanan istatistiksel hatalar (p (D) d D) oluşan D olasılık dağılımları; Homojen difüzyon modeli, D dağılımı Gauss (tek Gauss modeli) tarafından tarif edildiği birden fazla difüzyon modları ve birden fazla difüzyon modları, D dağılımı çok Gauss (çoklu Gauss modeli) ile ifade edilir. <ol><li> Homojen difüzyon modelde, bir denklem 22 kullanılarak D istatistiksel olasılık dağılımını hesaplamak <img alt="Equation7" src="/files/ftp_upload/54503/54503equation7.jpg" /> N difüzyon yörünge veri noktalarının sayısı (n = 10, 4.1.2) olduğu, D, 0 ortalama difüzyon katsayısı (CDF analizi ile tespit, 4.2.3.1 bakınız) ve D, deneysel olarak elde edilen bir bağımsız bir yörünge için difüzyon katsayısı. </li><li> içindeTek Gauss difüzyon modeli, bir denklem 15 kullanılarak D istatistiksel olasılık dağılımını hesaplamak <img alt="Equation8" src="/files/ftp_upload/54503/54503equation8.jpg" /> F (d) CDF analizi ile belirlenir D olasılık dağılımını (4.2.3.2 bakınız) temsil eder ve d, 0, ortalama difüzyon katsayısıdır (CDF analizi ile tespit, 4.2.3.2 bakınız). </li><li> Çift Gauss difüzyon modelinde, bir denklem 14 kullanılarak D istatistiksel olasılık dağılımını hesaplamak <img alt="Equation9" src="/files/ftp_upload/54503/54503equation9.jpg" /> F (d, J) CDF analizi ile belirlenmiştir D (d, J) bileşeni j nolu olasılık dağılımını ifade etmektedir (4.2.3.3 bakınız) ve D 0j CDF tarafından belirlenen bir bileşen TH J (ortalama difüzyon katsayısıdır analiz) 4.2.3.3 bkz. </li></ol></li></ol>

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D., Amis, E. J., Ferry, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-diffusion+in+solutions+of+polystyrene+in+tetrahydrofuran+-+comparison+of+concentration+dependences+of+the+diffusion-coefficients+of+polymers,+and+a+ternary+probe+component.">Self-diffusion in solutions of polystyrene in tetrahydrofuran - comparison of concentration dependences of the diffusion-coefficients of polymers, and a ternary probe component.</a> Macromolecules. 18 (2), 260-266 (1985).</li><li>Kapnistos, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unexpected+power-law+stress+relaxation+of+entangled+ring+polymers.">Unexpected power-law stress relaxation of entangled ring polymers.</a> Nat. Mater. 7 (12), 997-1002 (2008).</li><li>Adachi, K., Takasugi, H., Tezuka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Telechelics+having+unstrained+cyclic+ammonium+salt+groups+for+electrostatic+polymer+self-assembly+and+ring-emitting+covalent+fixation.">Telechelics having unstrained cyclic ammonium salt groups for electrostatic polymer self-assembly and ring-emitting covalent fixation.</a> Macromolecules. 39 (17), 5585-5588 (2006).</li><li>Oike, H., Imaizumi, H., Mouri, T., Yoshioka, Y., Uchibori, A., Tezuka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Designing+unusual+polymer+topologies+by+electrostatic+self-assembly+and+covalent+fixation.">Designing unusual polymer topologies by electrostatic self-assembly and covalent fixation.</a> J. Am. Chem. Soc. 122 (40), 9592-9599 (2000).</li><li>Yamamoto, T., Tezuka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Topological+polymer+chemistry:+a+cyclic+approach+toward+novel+polymer+properties+and+functions.">Topological polymer chemistry: a cyclic approach toward novel polymer properties and functions.</a> Polym. Chem. 2 (9), 1930-1941 (2011).</li><li>Habuchi, S., Fujiwara, S., Yamamoto, T., Tezuka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-molecule+imaging+reveals+topological+isomer-dependent+diffusion+by+4-armed+star+and+dicyclic+8-shaped+polymers.">Single-molecule imaging reveals topological isomer-dependent diffusion by 4-armed star and dicyclic 8-shaped polymers.</a> Polym. Chem. 6 (22), 4109-4115 (2015).</li><li>Habuchi, S., Fujiwara, S., Yamamoto, T., Vacha, M., Tezuka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-Molecule+Study+on+Polymer+Diffusion+in+a+Melt+State:+Effect+of+Chain+Topology.">Single-Molecule Study on Polymer Diffusion in a Melt State: Effect of Chain Topology.</a> Anal. Chem. 85 (15), 7369-7376 (2013).</li><li>Habuchi, S., Satoh, N., Yamamoto, T., Tezuka, Y., Vacha, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multimode+Diffusion+of+Ring+Polymer+Molecules+Revealed+by+a+Single-Molecule+Study.">Multimode Diffusion of Ring Polymer Molecules Revealed by a Single-Molecule Study.</a> Angew. Chem. Int. Ed. 49 (8), 1418-1421 (2010).</li><li>Habuchi, S., Tezuka, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Topological Polymer Chemistry: Progress of Cyclic Polymers in Syntheses, Properties and Functions. , 265-290 (2013).</li><li>Fernandez, P., Bayona, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+off-line+gel-remeation+chromatography+normal-phase+liquid-chromatography+fro+the+determination+of+polycyclic+aromatic-compounds+in+environmental-samples+and+standard+reference+materials+(air+particulate+matter+and+marine+sediment).">Use of off-line gel-remeation chromatography normal-phase liquid-chromatography fro the determination of polycyclic aromatic-compounds in environmental-samples and standard reference materials (air particulate matter and marine sediment).</a> J. Chromatogr. 625 (2), 141-149 (1992).</li><li>Biesenberger, J. A., Tan, M., Duvdevan, I., Maurer, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recycle+gel+permeation+chromatography.+1.+recycle+principle+and+design.">Recycle gel permeation chromatography. 1. recycle principle and design.</a> J. Polym. Sci. Pol. Lett. 9 (5), 353 (1971).</li><li>Kusumi, A., Sako, Y., Yamamoto, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Confined+lateral+diffusion+of+membrane-receptors+as+studied+by+single-particle+tracking+(nanovid+microscopy)+-+effects+of+calcium-induced+differentiation+in+cultured+epithelial-cells.">Confined lateral diffusion of membrane-receptors as studied by single-particle tracking (nanovid microscopy) - effects of calcium-induced differentiation in cultured epithelial-cells.</a> Biophys. J. 65 (5), 2021-2040 (1993).</li><li>Schutz, G. J., Schindler, H., Schmidt, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-molecule+microscopy+on+model+membranes+reveals+anomalous+diffusion.">Single-molecule microscopy on model membranes reveals anomalous diffusion.</a> Biophys. J. 73 (2), 1073-1080 (1997).</li><li>Vrljic, M., Nishimura, S. Y., Brasselet, S., Moerner, W. E., McConnell, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translational+diffusion+of+individual+class+II+MHC+membrane+proteins+in+cells.">Translational diffusion of individual class II MHC membrane proteins in cells.</a> Biophys. J. 83 (5), 2681-2692 (2002).</li><li>Margineanu, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photophysics+of+a+water-soluble+rylene+dye:+Comparison+with+other+fluorescent+molecules+for+biological+applications.">Photophysics of a water-soluble rylene dye: Comparison with other fluorescent molecules for biological applications.</a> J. Phys. Chem. B. 108 (32), 12242-12251 (2004).</li><li>Tezuka, Y., Oike, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-assembly+and+covalent+fixation+for+topological+polymer+chemistry.">Self-assembly and covalent fixation for topological polymer chemistry.</a> Macromol. Rapid Commun. 22 (13), 1017-1029 (2001).</li><li>Deres, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Origin+of+Heterogeneity+of+Polymer+Dynamics+near+the+Glass+Temperature+As+Probed+by+Defocused+Imaging.">The Origin of Heterogeneity of Polymer Dynamics near the Glass Temperature As Probed by Defocused Imaging.</a> Macromolecules. 44 (24), 9703-9709 (2011).</li><li>Flier, B. M. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneous+Diffusion+in+Thin+Polymer+Films+As+Observed+by+High-Temperature+Single-Molecule+Fluorescence+Microscopy.">Heterogeneous Diffusion in Thin Polymer Films As Observed by High-Temperature Single-Molecule Fluorescence Microscopy.</a> J. Am. Chem. Soc. 134 (1), 480-488 (2012).</li><li>Habuchi, S., Oba, T., Vacha, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-beam+single-molecule+defocused+fluorescence+imaging+reveals+local+anisotropic+nature+of+polymer+thin+films.">Multi-beam single-molecule defocused fluorescence imaging reveals local anisotropic nature of polymer thin films.</a> Phys. Chem. Chem. 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The authors have nothing to disclose.

4 kollu 8-şekilli polimerleri içerir. Sentez için önemli bir adımdır ESA CF protokolü (Şekil 1) yoluyla elde 12,24 tek fonksiyonlu ve iki fonksiyonlu lineer poli (THF) N S -phenylpiperidinium uç grupları olan edildi önceki edilen prosedüre göre sentezlendi. 11 iyon değişim karboksilat aşırı miktarını içeren bir sulu çözelti içine triflat karşı-bir polimer öncüsünün bir aseton çözeltisinin tekrar çökeltme işlemi ile gerçekleştirilmiştir...

Cyclic polymers are unique in that they do not have chain ends. They often exhibit unusual behaviors which is distinct from their linear counterpart, including increased thermal stability of polymer micelles by a linear-to-cyclic conversion,1,2 and spatial organization of DNA in bacterial cells by a loop formation.3 Topological interactions between the cyclic chains are believed to be the critical factor for such unusual behaviors.4,5 Therefore, characterizing the motion and relaxation of cyclic polymers under entangled conditions has been an important research topic in polymer science for decades.6
Cyclic polymer dynamics has been investigated using both synthetic and naturally occurring molecules by means of ensemble averaged experimental methods such as nuclear magnetic resonance (NMR), light scattering, and viscosity measurements.7-9 However, these studies often suffer from impurity molecules in the samples.10 Furthermore, spatiotemporal heterogeneities of the motion of individual molecules caused by inherent structural heterogeneity of entangled polymers are often hidden behind the ensemble averaging in these studies. In order to characterize molecular level dynamics of cyclic polymers, a synthesis method that provides high purity cyclic polymers and an experimental and analysis methods that allow for quantitative characterization of molecular motion at the single molecule level have to be developed. Here, we will show a method to synthesize high-purity cyclic and dicyclic poly(THF)s that incorporate a fluorophore unit using an electrostatic self-assembly and covalent fixation (ESA-CF) process11-13 and a method to analyze the motion of the individual fluorophore-incorporated polymer chains using a combination of mean-squared displacement (MSD) and cumulative distribution function (CDF) analyses.
A proper data processing has been shown to be essential for the accurate characterization of the diffusive motion. With an adequate MSD and CDF analyses, a multiple-mode diffusion of the cyclic and dicyclic polymers in the melt and semi-dilute solution of the linear polymer chains has been revealed,14-16 suggesting the significant effects of the topological states of the polymers on the diffusive motion of the chains under entangled conditions.17 While the experimental and analytical approaches to characterize the motion of the cyclic polymers are described in this protocol, the same method can be used to quantitatively characterize the diffusive motion in many other heterogeneous systems. The approach would be especially suitable when multiple diffusion components existing in the samples are to be analyzed.

<table><tbody><tr><td>&lt;strong&gt;Materials&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>THF</td><td>Godo</td><td></td><td></td></tr><tr><td>Wakosil C-300</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Acetone</td><td>Godo</td><td></td><td></td></tr><tr><td>Toluene</td><td>Godo</td><td></td><td></td></tr><tr><td>&lt;em&gt;n&lt;/em&gt;-Hexane</td><td>Godo</td><td></td><td></td></tr><tr><td>CHCl&lt;sub&gt;3&lt;/sub&gt;</td><td>Kanto Chemical</td><td></td><td></td></tr><tr><td>Bio-Beads S-X1</td><td>Bio-Rad</td><td></td><td></td></tr><tr><td>Methyl triflate</td><td>Nacalai Tesque</td><td></td><td></td></tr><tr><td>Triflic anhydride</td><td>Nacalai Tesque</td><td></td><td></td></tr><tr><td>Potassium Hydroxide</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Ethanol</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Poly(tetrahydrofuran)</td><td>Aldrich</td><td></td><td></td></tr><tr><td>Chloroform</td><td>Wako Pure Chemical Industries</td><td></td><td></td></tr><tr><td>Immersion oil</td><td>Cargille</td><td>Type 37 / Type A</td><td></td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>2-Neck 100-ml round-bottom flask</td><td></td><td></td><td></td></tr><tr><td>Flask</td><td></td><td></td><td></td></tr><tr><td>Beaker</td><td></td><td></td><td></td></tr><tr><td>Funnel</td><td></td><td></td><td></td></tr><tr><td>Filter paper</td><td>Whatman</td><td></td><td></td></tr><tr><td>Reflux condenser</td><td></td><td></td><td></td></tr><tr><td>Syringe</td><td></td><td></td><td></td></tr><tr><td>Water bath</td><td></td><td></td><td></td></tr><tr><td>Magnetic stirrer</td><td></td><td></td><td></td></tr><tr><td>Rotary evaporator</td><td></td><td></td><td></td></tr><tr><td>Microscope cover slips (24 x 24 mm, No. 1)</td><td>Matsunami Glass</td><td>CO22241</td><td></td></tr><tr><td>Staining jar</td><td>AS ONE Corporation</td><td>1-7934-01</td><td></td></tr><tr><td>Ultrasonic cleaner</td><td>VWR International&amp;nbsp;</td><td>142-0047</td><td></td></tr><tr><td>Inverted microscope</td><td>Olympus</td><td>IX71</td><td></td></tr><tr><td>Ar-Kr ion laser</td><td>Coherent</td><td>Innova 70C</td><td></td></tr><tr><td>Berek compensator</td><td>Newport</td><td>5540</td><td></td></tr><tr><td>Excitation filter</td><td>Semrock</td><td>LL01-488-12.5</td><td></td></tr><tr><td>Dichloric mirror</td><td>Omega optical</td><td>500DRLP</td><td></td></tr><tr><td>Emission filter</td><td>Semrock</td><td>BLP01-488R-25</td><td></td></tr><tr><td>Lens and mirror</td><td>Thorlabs</td><td></td><td></td></tr><tr><td>EM-CCD camera</td><td>Andor Technology</td><td>iXon</td><td></td></tr><tr><td>Objective lens (100X, N.A. = 1.3)</td><td>Olympus</td><td>UPLFLN 100XOP</td><td></td></tr><tr><td>Objective heater</td><td>Bioptechs</td><td></td><td></td></tr><tr><td>Preparative GPC</td><td>Japan Analytical Industry</td><td>LC-908</td><td></td></tr></tbody></table>

synthesis of cyclic polymers and characterization of their diffusive motion in the melt state at the single molecule level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis. The cyclic polymer exhibits multiple-mode diffusion which is distinct from its linear counterpart. The results demonstrate that the diffusional heterogeneity of polymers that is often hidden behind ensemble averaging can be revealed by the efficient synthesis of the cyclic polymers using the ESA-CF process and the quantitative analysis of the diffusive motion at the single molecule level using the MSD and CDF analyses.

Perilen 4 kollu yıldız ve diimid-dahil 8 şeklinde disiklik poli (THF) s elektrostatik kendini montaj ve kovalent tespit (ESA CF) işlemi (Şekil 1, Şekil 2) kullanılarak sentezlendi. Zaman atlamalı tek moleküllü Fluoresans görüntüleri 4-kollu (Şekil 3a) için ölçülmüş ve (Şekil 3b) polimerleri 8-şekillendirildi. Zaman atlamalı floresan görüntüleri (Şekil 3) mekansal nedeniyle zinc...

Watch this Scientific Journal Video about Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level at JoVE.com

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

sentez ve tek molekül düzeyinde halkalı polimerlerin uzadıya hareket karakterizasyonu için bir protokol sunulmuştur.

Tek Molekül Düzeyde Halkalı Polimerlerin Sentezi ve eritin Devlet Onların Pasif Hareket Karakterizasyonu

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single ...

synthesis-cyclic-polymers-characterization-their-diffusive-motion

Universidad San Sebastian

Research

JoVE Journal

Chemistry

7.8K Görüntüleme.  King Abdullah University of Science and Technology (KAUST).  sentez ve tek molekül düzeyinde halkalı polimerlerin uzadıya hareket karakterizasyonu için bir protokol sunulmuştur. 

Video: Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this work, we use single particle tracking of fluorescently labeled PNIPAM microgels as a showcase for tuning microgel size by a rapid non-stirred precipitation polymerization procedure. This approach is well suited for prototyping new reaction compositions and conditions or for applications that do not require large amounts of product. Microgel synthesis, particle size and structure determination by dynamic and static light scattering are detailed in the protocol. It is shown that the addition of functional comonomers can have a large influence on the particle nucleation and structure. Single particle tracking by wide-field fluorescence microscopy allows for an investigation of the diffusion of labeled tracer microgels in a concentrated matrix of non-labeled microgels, a system not easily investigated by other methods such as dynamic light scattering.

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Non-stirred precipitation polymerization provides a rapid, reproducible prototyping approach to the synthesis of stimuli-sensitive poly(N-isopropylacrylamide) microgels of narrow size distribution. In this protocol synthesis, light scattering characterization and single particle fluorescence tracking of these microgels in a wide-field microscopy setup are demonstrated.

Kontrollü Sentezi ve yüksek Düzgün Poli Floresan Takibi (<em&gt; K</em&gt; -isopropylacrylamide) Mikrojeller

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this ...

Kimya

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives

A facile method for the preparation of polycarbodiimide-based secondary structures (e.g., nano-rings, &#34;craters,&#34; fibers, looped fibers, fibrous networks, ribbons, worm-like aggregates, toroidal structures, and spherical particles) is described. These aggregates are morphologically influenced by extensive hydrophobic side chain-side chain interactions of the singular polycarbodiimide strands, as inferred by atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. Polycarbodiimide-g-polystyrene copolymers (PS-PCDs) were prepared by a combination of synthetic methods, including coordination-insertion polymerization, copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) &#34;click&#34; chemistry, and atom transfer radical polymerization (ATRP). PS-PCDs were found to form specific toroidal architectures at low concentrations in CHCl3. To determine the influence of a more polar solvent medium (i.e., THF and THF/EtOH) on polymer aggregation behavior, a number of representative PS-PCD composites have been tested to show discrete concentration-dependent spherical particles. These fundamental studies are of practical interest to the development of experimental procedures for desirable architectures by directed self-assembly in thin film. These architectures may be exploited as drug carriers, whereas other morphological findings represent certain interest in the area of novel functional materials.

Here, we present a protocol to prepare and visualize secondary structures (e.g., fibers, toroidal architectures, and nano-spheres) derived from helical polycarbodiimides. The morphology characterized by both atomic force microscopy (AFM) and scanning electron microscopy (SEM) was shown to depend on molecular structure, concentration, and the solvent of choice.

Sarmal polikarbodiimidden Kopolimer ve Bunların Triazole Türevleri elde edilen kendinden montaj morfolojileri

A facile method for the preparation of polycarbodiimide-based secondary structures (e.g., nano-rings, &#34;craters,&#34; fibers, looped fibers, fibrous ...

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in Poly(S-Divinylbenzene)

Elemental sulfur (S8) is a byproduct of the petroleum industry with millions of tons produced annually. Such abundant production and limited applications lead to sulfur as a cost-efficient reagent for polymer synthesis. Inverse vulcanization combines elemental sulfur with a variety of monomers to form functional polysulfides without the need for solvents. Short reaction times and straight forward synthetic methods have led to rapid expansion of inverse vulcanization. However, high reaction temperatures (&#62;160 &#176;C) limit the types of monomers that can be used. Here, the dynamic sulfur bonds in poly(S-divinylbenzene) are used to initiate polymerization at much lower temperatures. The S-S bonds in the prepolymer are less stable than S-S bonds in S8, allowing radical formation at 90 &#176;C rather than 159 &#176;C. A variety of allyl and vinyl ethers have been incorporated to form terpolymers. The resulting materials were characterized by 1H NMR, gel permeation chromatography, and differential scanning calorimetry, as well as examining changes in solubility. This method expands on the solvent-free, thiyl radical chemistry utilized by inverse vulcanization to create polysulfides at mild temperatures. This development broadens the range of monomers that can be incorporated thus expanding the accessible material properties and possible applications.

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in PolyS-Divinylbenzene

The goal of this protocol is to initiate polymerization using dynamic sulfur bonds in poly(S-divinylbenzene) at mild temperatures (90 &#176;C) without using solvents. Terpolymers are characterized by GPC, DSC and 1H NMR, and tested for changes in solubility.

Poly (S-Divinylbenzene) dinamik sülfür bağları kullanarak hafif sıcaklıklarda Terpolimerler sentezi

Elemental sulfur (S8) is a byproduct of the petroleum industry with millions of tons produced annually. Such abundant production and limited applications ...

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock copolymers are produced by one of three techniques: thin film rehydration, solvent switching or polymerization-induced self-assembly, and produce only flexible, polydisperse cylinders. Crystallization-driven self-assembly (CDSA) is a method which can produce cylinders with these properties, by stabilizing structures of a lower curvature due to the formation of a crystalline core. However, the living polymerization techniques by which most core-forming blocks are formed are not trivial processes and the CDSA process may yield unsatisfactory results if carried out incorrectly. Here, the synthesis of cylindrical nanoparticles from simple reagents is shown. The drying and purification of reagents prior to a ring-opening polymerization of &#949;-caprolactone catalyzed by diphenyl phosphate is described. This polymer is then chain extended by methyl methacrylate (MMA) followed by N,N-dimethyl acrylamide (DMA) using reversible addition&#8722;fragmentation chain-transfer (RAFT) polymerization, affording a triblock copolymer that can undergo CDSA in ethanol. The living CDSA process is outlined, the results of which yield cylindrical nanoparticles up to 500 nm in length and a length dispersity as low as 1.05. It is anticipated that these protocols will allow others to produce cylindrical nanostructures and elevate the field of CDSA in the future.

Crystallization-driven self-assembly (CDSA) displays the unique ability to fabricate cylindrical nanostructures of narrow length distributions. The organocatalyzed ring-opening polymerization of &#949;-caprolactone and subsequent chain extensions of methyl methacrylate and N,N-dimethyl acrylamide are demonstrated. A living CDSA protocol that produces monodisperse cylinders up to 500 nm in length is outlined.

Biodegradable blok kopolimerlerin kristalizasyon Driven kendinden montajı ile Monodisperse silindirik Nanopartiküllerin sentezini

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package

We have developed a Python-based open-source package to analyze the results stemming from ab initio molecular-dynamics simulations of fluids. The package is best suited for applications on natural systems, like silicate and oxide melts, water-based fluids, and various supercritical fluids. The package is a collection of Python scripts that include two major libraries dealing with file formats and with crystallography. All the scripts are run at the command line. We propose a simplified format to store the atomic trajectories and relevant thermodynamic information of the simulations, which is saved in UMD files, standing for Universal Molecular Dynamics. The UMD package allows the computation of a series of structural, transport and thermodynamic properties. Starting with the pair-distribution function it defines bond lengths, builds an interatomic connectivity matrix, and eventually determines the chemical speciation. Determining the lifetime of the chemical species allows running a full statistical analysis. Then dedicated scripts compute the mean-square displacements for the atoms as well as for the chemical species. The implemented self-correlation analysis of the atomic velocities yields the diffusion coefficients and the vibrational spectrum. The same analysis applied on the stresses yields the viscosity. The package is available via the GitHub website and via its own dedicated page of the ERC IMPACT project as open-access package.

Melts and fluids are ubiquitous vectors of mass transport in natural systems. We have developed an open-source package to analyze ab initio molecular-dynamics simulations of such systems. We compute structural (bonding, clusterization, chemical speciation), transport (diffusion, viscosity) and thermodynamic properties (vibrational spectrum).

AB Initio Moleküler Dinamik Simülasyonlarından Eriyik ve Sıvıların UMD Paketi ile Analizi

We have developed a Python-based open-source package to analyze the results stemming from ab initio molecular-dynamics simulations of fluids. The package ...

Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer

The development of chemically recyclable biopolymers offers opportunities within the pursuit of a circular economy. Chemically recyclable biopolymers make a positive effort to solve the issue of polymer materials in the disposal phase after the use phase. In this paper, the production of biobased semi-aromatic polyesters, which can be extracted entirely from biomass such as lignin, is described and visualized. The polymer poly-S described in this paper has thermal properties similar to certain commonly used plastics, such as PET. We developed a Green Knoevenagel reaction, which can efficiently produce monomers from aromatic aldehydes and malonic acid. This reaction has been proven to be scalable and has a remarkably low calculated E-factor. These polyesters with ligno-phytochemicals as a starting point show an efficient molecular recycling with minimal losses. The polyester poly(dihydrosinapinic acid) (poly-S) is presented as an example of these semi-aromatic polyesters, and the polymerization, depolymerization, and re-polymerization are described.

An example of a closed-loop approach towards a circular materials economy is described here. A whole sustainable cycle is presented where biobased semi-aromatic polyesters are designed by polymerization, depolymerization, and then re-polymerized with only slight changes in their yields or final properties.

Moleküler Geri Dönüşüm için Tasarlanmıştır: Lignin Türevi Yarı Aromatik Biyobaz Polimer

The development of chemically recyclable biopolymers offers opportunities within the pursuit of a circular economy. Chemically recyclable biopolymers make ...

Methods for the Self-integration of Megamolecular Biopolymers on the Drying Air-LC Interface

Living organisms that use water are always prone to drying in the environment. Their activities are driven by biopolymer-based micro- and macro-structures, as seen in the cases of moving water in vascular bundles and moisturizing water in skin layers. In this study, we developed a method for assessing the effect of aqueous liquid crystalline (LC) solutions composed of biopolymers on drying. As LC biopolymers have megamolecular weight, we chose to study polysaccharides, cytoskeletal proteins, and DNA. The observation of biopolymer solutions during drying under polarized light reveals milliscale self-integration starting from the unstable air-LC interface. The dynamics of the aqueous LC biopolymer solutions can be monitored by evaporating water from a one-side-open cell. By analyzing the images taken using cross-polarized light, it is possible to recognize the spatio-temporal changes in the orientational order parameter. This method can be useful for the characterization of not only artificial materials in various fields, but also natural living tissues. We believe that it will provide an evaluation method for soft materials in the biomedical and environmental fields.

A method for the drying-induced self-integration of megamolecular biopolymers on the air-liquid crystalline interface is provided here. This methodology will be useful not only for understanding the macroscopic potentials of biopolymers, but also as an evaluation method for soft materials in biomedical and environmental fields.

Kurutma Hava-LC Arayüz üzerinde Megamolecular Biyopolimerlerin Kendinden entegrasyonu için Yöntemler

Living organisms that use water are always prone to drying in the environment. Their activities are driven by biopolymer-based micro- and ...

Biyomühendislik

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

The growing consumption of synthetic polymers and the accumulation of polymer waste have led to a pressing need for new routes to sustainable materials. Achieving a closed-loop polymer economy via chemical recycling to monomer (CRM) is one such promising route. Our group recently reported a new CRM system based on polymers prepared by ring-opening metathesis polymerization (ROMP) of trans-cyclobutane fused cyclooctene (tCBCO) monomers. This system offers several key advantages, including the ease of polymerization at ambient temperatures, quantitative depolymerization to monomers under mild conditions, and a broad range of functionalities and thermomechanical properties. Here, we outline detailed protocols for the preparation of tCBCO-based monomers and their corresponding polymers, including the preparation of elastic polymer networks and compression molding of linear thermoplastic polymers. We also outline the preparation of high ring strain E-alkene tCBCO monomers and their living polymerization. Finally, the procedures for the depolymerization of linear polymers and polymer networks are also demonstrated.

Here, we describe protocols for the preparation of trans-cyclobutane fused cyclooctenes (tCBCO),&#160;their polymerization to prepare depolymerizable olefinic polymers, and the depolymerization of these polymers under mild conditions. Additionally, protocols for the preparation of depolymerizable networks and compression molding of rigid linear plastics based on this system are described.

Kaynaşmış Halka Siklookten Monomerlerine Dayanan Depolimerize Edilebilir Olefinik Polimerler

The growing consumption of synthetic polymers and the accumulation of polymer waste have led to a pressing need for new routes to sustainable materials. ...

Polymerization

Source: Vy M. Dong and Jan Riedel, Department of Chemistry, University of California, Irvine, CA
Polymers are made from macromolecules, which are composed of repeating units (the so called monomeric units). In our modern world, polymers play an important role. One of the first important polymers was nylon, which is a polyamide. It found widespread application in tooth brushes and stockings.

Polymerization: Types of Polymerizations and Applications

Source: Vy M. Dong and Jan Riedel, Department of Chemistry, University of California, Irvine, CA
Polymers are made from macromolecules, which are composed ...

Education

JoVE Science Education

Organik Kimya II

Kinetics of Addition Polymerization to Polydimethylsiloxane

Source: <a href="https://www-jove-com.bdigitaluss.remotexs.co/author/Kerry+M._Dooley">Kerry M. Dooley</a> and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymers are molecules consisting of many repeating monomer units that are chemically bonded into long chains. They exhibit a broad range of physical properties, which are affected by their chemical structure, molecular weight and degree of polymerization. The polymer industry manufactures thousands of raw materials used in a broad variety of commercial products.1,2
The goal of this video is to perform an addition polymerization reaction and then evaluate the resulting product to understand how viscosity can be used to determine polymer molecular weight. Additionally, this experiment will investigate how molecular weight can be related to monomer conversion.

Synthesis of Polydimethylsiloxane via Addition Polymerization

Source: Kerry M. Dooley and Michael G. Benton, Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA
Polymers are molecules ...