End group functionality of 95–99% : epoxide functionalization of polystyryl-lithium evaluated via solvent gradient interaction chromatography

End group functionality is a key parameter of functional polymer chains. The end-capping efficiency of living polystyryl lithium with various epoxides, namely ethylene oxide (EO), ethoxy ethyl glycidyl ether (EEGE) and isopropylidene glyceryl glycidyl ether (IGG), is investigated with solvent gradient interaction chromatography (SGIC). Generally, end-capping efficiencies >95% are observed. Hydroxy functional polystyrene (PS–OH, PS–EEGE–OH, and PS–IGG–OH) with molar masses ranging from 13.8 to 15.0 kg mol−1 are obtained, with dispersities of 1.05–1.06. Deprotection of the acetal (PS–EEGE–OH) and ketal protective group (PS–IGG–OH) is investigated. Nearly quantitative deprotection (>99%) resulting in the corresponding multihydroxy functional PS (PS–(OH)2 and PS–(OH)3) are observed via SGIC. Esterification of PS–OH with succinic anhydride shows a conversion of 98% to the corresponding ester. A detailed picture of side reactions during the carbanionic polymer synthesis subsequent epoxide termination is obtained, demonstrating 95–99% terminal functionality. Depending on the polarity of the end group, an elution order of PS–OH < PS–(OH)2 < PS–(OH)3 < PS–COOH is obtained in SGIC. The study demonstrates both the analytical power of SGIC and the exceptionally high terminal functionalization efficiency of anionic polymerization methods

Structural characterization of the Fddd phase in a diblock copolymer thin film by electron microtomography

A 3-dimensional Fddd network structure of a polystyrene-block-polyisoprene (PS-b-PI) diblock copolymer (M(n) = 31 500, f(PI) = 0.645) was observed for the first time in real space by transmission electron microtomography (TEMT). In a 650 nm thick film of the PS-b-PI thin film on a silicon wafer, the Fddd phase was developed after annealing at 215 degrees C for 24 h. The single network structure consists of the connected tripodal units of minor PS block domains. The {111}(Fddd) plane, the densest plane of the minor PS phase, was found to orient parallel to the film plane. The transitional structure from the wetting layer at the free surface to the internal {111}(Fddd) plane via a perforated layer structure was also observed.X111313sciescopu

Characterization of a 4-miktoarm star copolymer of the (PS-b-PI) 3 PS type by temperature gradient interaction chromatography

Abstract Temperature gradient interaction chromatography (TGIC) was applied for the separation of a complex miktoarm star copolymer which has one polystyrene (PS) arm and three polystyrene-b-polyisoprene (PS-b-PI) diblock copolymer arms. Such miktoarm star polymers are much more difficult to characterize than branched homopolymers since the byproduct, typically polymers with missing arm(s) or coupled products, have not only different molecular weights but also different compositions. TGIC was able to fully separate the byproducts, and the composition of the molecular species corresponding to the different separated elution peaks was determined by two methods, fractionation/NMR and multiple detection (UV and RI). A reasonable agreement between the results of the two methods was obtained. By using the composition found, the corresponding molecular weights were determined by multi-angle light scattering detection. Based on the composition and the molecular weight we were able to identify the structure of the different molecular species

Colloidal gelation induced by ring polymers

The computational results presented here have been achieved using the Vienna Scientific Cluster (VSC).-- QLUSTER Project (Quantum and Classical Ultrasoft Matter), Grant agreement ID: 101072964. Coordinated by CSIC (Centro de Física de Materiales, CFM). Partner/Coordinador principal: Ángel moreno Asegurado.We provide unambiguous experimental evidence that ring polymers are stronger depleting agents in colloidal suspensions than their linear counterparts. We use an intermediate volume fraction (ϕc=0.44) colloidal gel based on the classic poly(methyl methacrylate) (PMMA) hard spheres, in which the polystyrene depletant is either linear or ring of the same molar mass or the same size. We systematically increase the depletant concentration from zero (no attraction) to well above the gelation point and find that in the presence of rings, gels are formed at smaller concentrations and possess a larger storage modulus in comparison to those induced by the linear chains. Consequently, the yield stress is enhanced; however, the yield strain (gel deformability) remains concomitantly unaffected. Our experimental findings are in agreement with theoretical calculations based on effective interaction potentials. Hence, polymer architecture is a powerful entropic tool to tailor the strength of colloidal gels.S.A.E. acknowledges financial support from the Erwin Schrödinger International Institute for Mathematics and Physics (ESI) as a Senior Research Fellow. We acknowledge support by a FORTH synergy grant (RINGS) and from the European Union (Horizon-MSCA-Doctoral Networks) through the project QLUSTER (HORIZON-MSCA-2021-DN-01-GA101072964).Peer reviewe

Influence of the Solvent Quality on Ring Polymer Dimensions

We present a systematic investigation of well-characterized, experimentally pure polystyrene (PS) rings with molar mass of 161 000 g/mol in dilute solutions. We measure the ring form factor at θ - and good-solvent conditions as well as in a polymeric solvent (linear PS of roughly comparable molar mass) by means of small-angle neutron scattering (SANS). Additional dynamic light scattering (DLS) measurements support the SANS data and help elucidate the role of solvent quality and solution preparation. The results indicate the increase of ring dimensions as the solvent quality improves. Furthermore, the experimental form factors in both θ -solvent and linear matrix behave as ideal rings and are fully superimposable. The nearly Gaussian conformations of rings in a melt of linear chains provide evidence of threading of linear chains through rings. The latter result has implications for the dynamics of ring-linear polymer mixtures

A brief guide to polymer characterization: structure (IUPAC technical report)

To bolster the series of Brief Guides released by International Union of Pure and Applied Chemistry (IUPAC), here we introduce the first Brief Guide to Polymer Characterization. This article provides a concise overview of characterization methods for teachers, students, non-specialists, and newcomers to polymer science as well as being a useful manual for researchers and technicians. Unlike pure low molar mass chemical substances, polymers are not composed of identical molecules. The macromolecules which comprise a single polymer sample vary from one another, primarily in terms of size and shape, but often also in the arrangement or positioning of atoms within macromolecules (e.g., chain branching, isomerism, etc.). Polymer properties are often drastically different from those of other substances and their characterization relies on specialist equipment and/or common equipment used in a specialized way (e.g., particular sample preparation or data analysis). This Brief Guide focuses uniquely on the structural characterization (i.e., analyzing the molecular and multi-molecular aspects) of polymers. The complex nature of the structural variables possible in macromolecular materials often presents a challenge with regard to the detailed structural characterization of polymers. This Brief Guide provides a useful starting point to direct the reader to the most commonly used and useful techniques to characterize these structural variables

Purification and characterization of cyclic polymers

11Nsci

Relationship of Molecular Weight and Glass Transition Temperature of Tri-cyclic Polystyrene

2

Separation and characterization of living and dead chains in polystyrene synthesized by ATRP

1