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.).

<ol>
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The authors have nothing to disclose.

Die 4-armed und 8 förmige Polymere wurden über die ESA-CF - Protokoll (1) hergestellt, die ein kritischer Schritt für die Synthese ist. 12,24 mono- und bifunktionelle lineare Poly (THF) s mit N -phenylpiperidinium Endgruppen waren nach dem vorstehenden Verfahren synthetisiert. 11 der Ionenaustausch wurde durch Umfällung aus einer Aceton - Lösung eines Polymervorläufers mit Triflat Gegenanionen in eine wässrige Lösung , die eine überschüssige Menge an carboxylat durchgeführt. Die kovalente Umwandlung des Ionenaustauschprodukt für die 4-armigen Stern-Polymeren wurde in Toluol (4,9 g / L) durch Rückfluss für 4 Stunden durchgeführt. Wenn die Umwandlung nicht ausreichend ist, verlängern die Reaktionszeit. Das kovalent gebundene Produkt wurde durch Kieselgel-Säulenchromatographie mit Aceton / n - Hexan und Umfällen in Wasser erhalten. Das 1 H - NMR der 4-armed Polymeren ist in 2a gezeigt. This ESA-CF Verfahren ermöglicht die effektive Synthese von zyklischen Polymeren. Jedoch wird dieses Protokoll auf Polymere beschränkt, die cyclische Onium-Endgruppen aufweisen. Für den 8-förmigen Polymerprodukt wurde die Reaktion in Toluol in Verdünnung (0,2 g / l) unter Rückfluß 4 h und führte zur Bildung eines großen Teils einer unlöslichen Fraktion durchgeführt wird, vermutlich aufgrund der intermolekularen Produkten umgesetzt. Eine lösliche Anteil wurde in n - Hexan, unterworfen , um Silicagel-Säulenchromatographie mit Aceton / n - Hexan, umgefällt und in Wasser erneut ausgefällt. Das erhaltene Rohprodukt wurde einer Säulenchromatographie mit Grßenausschluß beads unterworfen und GPC recyclen Isolierung des 8-förmigen Polymerprodukt zu ermöglichen. Das 1 H - NMR der 8-förmigen Polymeren ist in 2b gezeigt. Das ESA-CF-Protokoll kann auf weitere komplexe topologische Polymere anwendbar. Die hohe Qualität der Fluoreszenzbilder sind Essential für die genaue Analyse der diffusiven Bewegung der Moleküle. Die Fluoreszenzbilder signifikant verschlechtert werden, wenn 1) Fluoreszenz Verunreinigungen in der Probe vorhanden sind, 2) die Fluoreszenzquantenausbeute eines eingebauten Fluorophor niedrig ist, und 3) die Bildfrequenz des Bilderzeugungs langsamer ist als die Diffusionsbewegung der Polymermoleküle. Einstellen der Temperatur unterhalb der Raumtemperatur (20 ° C) oder oberhalb 37 ° C einen Brechungsindex-Fehlanpassung verursachen, die auch die Qualität der aufgezeichneten Fluoreszenzbilder verschlechtert. ein engeres Band Emissionsbandfilter auf einem Filterwürfel verbessert die Qualität des Fluoreszenzbildes einmal montiert werden. Da die Belichtungszeit der EM-CCD-Kamera im Abbildungs ​​Experiment verwendet üblicherweise Millisekunden begrenzt ist, kann die Diffusionsbewegung schneller als dieser Zeitskala durch dieses Verfahren nicht erfasst werden. Die Bewertung der Wirkung der statistischen Fehler in der MSD-Analyse ist der kritische Schritt for die Charakterisierung der heterogenen Diffusion. Der statistische Fehler sorgfältig durch Berechnung der Wahrscheinlichkeitsverteilung des Diffusionskoeffizienten ausgewertet werden soll , die homogene Diffusionsmodell 22 vor der Diskussion der heterogenen Diffusions verwenden. Die heterogene Diffusion sollte auch sorgfältig von der CDF-Analyse ausgewertet werden. Wenn die CDF deutliche Abweichungen vom homogenen Diffusionsmodell zeigen (dh Single-exponentielle abklingenden Kurve), deutet dies auf das Vorhandensein von mehreren Diffundieren Komponenten. Die quantitative Charakterisierung von heterogenen Diffusion erfordert kombinierte MSD, CDF und Wahrscheinlichkeitsverteilung analysiert. 14,15 Polymer Dynamik, einschließlich Diffusionsbewegung, wurde als Ensemble-Mittelwerte in den herkömmlichen Verfahren, wie NMR, Lichtstreuung 7, 8 und Viskositätsmessungen. 9 beschrieben Tatsächlich ist die heterogene durch die singl ergab Diffusionsbewegunge-Molekül Abbildungs 16 ist oft sehr schwierig , im Ensemble gemittelten Methoden zu erfassen. Die inhärente Heterogenität von Polymeren Berücksichtigung 25-27 Das Verfahren in diesem Protokoll angegeben ist nicht auf die Charakterisierung von topologische Polymere beschränkt, sondern ist auf alle Arten von Polymeren , die unter verschränkter Bedingungen anwendbar. 28 Ferner ist die Vorgehensweise in diesem Protokoll gemeldet werden feststellen , eine breite Anwendung in der Analyse der heterogenen Diffusion in komplexen Systemen, wie beispielsweise molekularen Diffusion durch mesoporöse Materialien. 29

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.

Die Perylendiimid-4 enthalten einarmigen Stern und 8-förmigen dicyclic Poly (THF) s wurden unter Verwendung der elektrostatische Selbstorganisation und kovalente Fixierung synthetisiert (ESA-CF) Prozess (Abbildung 1, Abbildung 2). Zeitraffer-Einzelmolekül - Fluoreszenzbilder wurden für die 4-armed (Abbildung 3a) gemessen und 8-förmigen (Abbildung 3b) Polymere. Die Zeitraffer-Fluoreszenzbilder (Abbildung 3) zeigen räumlich getrennt hell und scharf Flecken durch den Einbau des stark fluoreszierenden Perylendiimid Fluorophor 23 in den Ketten. Frequenz - Histogramme des Diffusionskoeffizienten wurden für die 4-armed (4a) berechnet und 8-förmigen (4b) Polymere , die durch die mittlere quadratische Verschiebung (MSD) Analyse der Zeitraffer-Bilder. Die Berechnungen von MSD Plots und CDF verwenden Routinen in MATLAB geschrieben durchgeführt. Der Beschlagder CDFs aus den Experimenten erhalten wird, durchgeführt, Datenverarbeitungssoftware wie Origin Pro. Die Frequenzhistogramme des Diffusionskoeffizienten von der MSD - Analyse bestimmt anzuzeigen breite Verteilungen (Abbildung 4) , die aus sowohl den statistischen Fehler der Analyse und der Heterogenität der Diffusion. Die Frequenz Histogramme zeigen deutliche Abweichungen vom homogenen Diffusionsmodell (grüne Linie in Abbildung 4), die heterogene Diffusion der Polymermoleküle zeigt. 14 Kumulative Verteilungsfunktionen (CDF) für die 4-armed (5a) berechnet wurden , und 8-förmige (5b) Polymere und durch die einzige Gauß&#39;sche (5a) versehen und Doppel Gaussian (5b) modelliert. Die statistischen Wahrscheinlichkeitsverteilungen des Diffusionskoeffizienten wurden für die 4-armigen (4a) berechnet und 8-förmig (Figur 4b) pol<html> Polymere durch die einzelne Gauß-oder Doppel Gauß-Modelle. Die einzige (5a) und Doppel (5b) Gaußsche Modelle passen auf die experimentell gut erhaltenen CDF. Diese Ergebnisse zeigen, daß die Diffusion des 4-armed Polymer durch die breite Verteilung des Diffusionskoeffizienten beschrieben, während der 8-förmigen Polymer zeigt zwei unterschiedliche Diffusionsmodus. <img alt="Abbildung 1" src="/files/ftp_upload/54503/54503fig1.jpg" /> Abbildung 1. Syntheseweg von Perylendiimid-inkorporiert Poly (THF) s. Syntheseweg von (a) 4-armed Sternpolymere und (b) 8-förmigen dicyclic Polymere. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig1large.jpg" target="_blank">Bitte klicken Sie hier</a> , um <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig1large.jpg" target="_blank">eine größere Version dieser Figur zu sehen.</a> <html> 54503fig2.jpg &quot;/&gt; Abbildung 2. Charakterisierung der synthetisierten Polymere. NMR - Spektren von (a) 4-armed Sternpolymere und (b) 8-förmigen dicyclic Polymere. <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig2large.jpg" target="_blank">Bitte klicken Sie hier</a> , um <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig2large.jpg" target="_blank">eine größere Version dieser Figur zu sehen.</a> <img alt="Figur 3" src="/files/ftp_upload/54503/54503fig3.jpg" /> Abbildung 3 (Filme). Einzelmolekül - Fluoreszenz - Bildgebung des Perylendiimid-inkorporiert Poly (THF) s. Zeitraffer-Fluoreszenzbilder von (a) 4-armed Sternpolymere und (b) 8-förmigen dicyclic Polymere in der Schmelze von nicht markierten linearen Poly (THF ). Maßstabsbalken = 5 &amp; mgr; m. Bitte klicken Sie hier Filme zu sehen <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/Figure_3a_submit.mov" target="_blank">(a)</a> und3 / Figure_3b_submit.mov &quot;target =&quot; _ blank &quot;&gt; (b). <img alt="Abbildung 4" src="/files/ftp_upload/54503/54503fig4.jpg" /> Abbildung 4. MSD - Analyse des Perylendiimid-inkorporiert Poly (THF) s in der Schmelze diffundieren. Frequenz Histogramme des Diffusionskoeffizienten bestimmt für einzelne (a) 4-armed Sternpolymere und (b) 8-förmigen dicyclic Polymere in der Schmelze von linearen Poly (THF) nicht markiert. Die durchgezogenen Linien zeigen theoretisch Wahrscheinlichkeitsverteilungen des Diffusionskoeffizienten berechnet, basierend auf den drei unterschiedlichen Diffusionsmodellen; homogenen Diffusionsmodell (grüne Linien, siehe 4.3.1), einzelne Gauß - Modell (Redlining, siehe 4.3.2) und Doppel - Gauß - Modell (blaue Linie, siehe 4.3.3). 14 <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig4large.jpg" target="_blank">Bitte hier klicken</a> , um <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig4large.jpg" target="_blank">eine größere Version davon zu sehen Zahl.</a> Abbildung 5. CDF Analyse der Perylendiimid-eingebaut Poly (THF) s in der Schmelze diffundieren Experimentell erhaltene kumulative Verteilungsfunktionen (iΔt = 7,5 bis 75 ms). In Form von 1-P für (a) 4-armed Sternpolymere und (b) 8-förmigen dicyclische Polymeren in der Schmelze der nicht-markierten linearen Poly (THF). Eine gestrichelte Linien zeigen Armaturen mit (a) Gleichungen in 4.2.3.2 und (b) Gleichungen in 4.2.3.3. 14 <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig5large.jpg" target="_blank">Bitte hier klicken</a> , um <a href="https://www-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/54503/54503fig5large.jpg" target="_blank">eine größere Version dieser Figur zu sehen.</a>

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

Ein Protokoll für die Synthese und Charakterisierung von Diffusionsbewegung von zyklischen Polymeren auf der Einzelmolekülebene vorgestellt.

Synthese cyclischer Polymere und Charakterisierung ihrer Diffusionsbewegung im geschmolzenen Zustand auf der Einzelmolekülebene

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

Nanyang Technological University

Research

JoVE Journal

Chemistry

7.8K Aufrufe.  King Abdullah University of Science and Technology (KAUST).  Ein Protokoll für die Synthese und Charakterisierung von Diffusionsbewegung von zyklischen Polymeren auf der Einzelmolekülebene vorgestellt. 

Serie: 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.

Kontrollierte Synthese und Fluoreszenz-Tracking von Hoch Uniform Poly (<em&gt; N</em&gt; Isopropylacrylamid) Mikrogele

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

Forschung

Chemie

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.

Selbstaufbau Morphologien Gewonnen aus Helical Polycarbodiimid-Copolymere und deren Triazolderivate

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.

Synthese von Terpolymeren bei Mildtemperaturen mit dynamischen Schwefelbonds 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 ...

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.

Synthese von monodispersen zylindrischen Nanopartikeln durch kristallisationsgesteuerte Selbstmontage von biologisch abbaubaren Blockcopolymeren

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).

Analyse von Schmelzen und Flüssigkeiten aus Ab Initio Molekulardynamiksimulationen mit dem UMD-Paket

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.

Entwickelt für molekulares Recycling: Ein aus Lignin gewonnenes halbaromatisches biobasiertes Polymer

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.

Methoden zur Selbst Integration von Megamolecular Biopolymere auf der Trocknungsluft-LC-Schnittstelle

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

Biotechnik

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.

Depolymerisierbare olefinische Polymere auf Basis von Cyclooctenmonomeren mit Schmelzring

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

Polymerisation

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

Lehre

JoVE Science Education

Organische Chemie 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

Kinetik der Additionspolymerisation zu Polydimethylsiloxan

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