Polymer Chemistry Blog

Light induced thermocleaving of a thermally reactive copolymer based on dithienylthiazolo[5,4-d]thiazole (DTZ) and silolodithiophene (SDT) in contact with the heat sensitive substrate polyethyleneterphthalate (PET) was effectively demonstrated with the use of high intensity pulsed light, delivered by a commercial photonic sintering system. Thermally labile ester groups are positioned on the DTZ unit of the copolymer that can be eliminated thermally for enhanced photochemical stability and advantages in terms of processing (solubility/insolubility switching). The photonic sintering system was successfully implemented in a full roll-to-roll process on flexible PET substrates and large-area polymer solar cell modules were prepared by solution processing of five layers under ambient conditions using the photonic sintering system for thermocleaving of the active layer. The PET foil did not show any deformation after exposure to the high intensity light only leaving the insoluble thermocleaved active layer. The active layer remained planar after light exposure thereby allowing the coating of supplementary material on top.

Amphiphilic polymers have been synthesised by controlled free radical polymerisation techniques. These polymers self-assemble into well-defined vesicles in aqueous conditions, enabling encapsulation of a model hydrophilic molecule. The polymeric vesicles show high stability against a range of aqueous conditions with marginal release of cargo, even in the presence of known cell-membrane disruptive polymers such as branched poly(ethylene imine) (b-PEI). This stability allows for inversion of the surface charge of the polymeric vesicles by a simple coating protocol leading to an enhanced uptake by mammalian cells.

Well-defined polymeric vesicles with high stability and modulation of cell uptake by a simple coating protocol Gökçen Yaşayan, Martin Redhead, Johannes P. Magnusson, Sebastian G. Spain, Stephanie Allen, Martyn Davies, Cameron Alexander and Francisco Fernández-Trillo Polym. Chem., 2012, 3, 2596-2604.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistry on Twitter or Facebook.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistry on Twitter or Facebook.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.

Synthesis and post-polymerization modification of poly(pentafluorophenyl methacrylate) brushes by Kemal Arda Günay, Nicolas Schüwer and Harm-Anton Klok Polym. Chem. 2012, 3, 2186-2192.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.

Synthesis and charge-transporting properties of electron-deficient CN2–fluorene based D–A copolymers by Jianhua Huang, Yan Zhao, Xunlei Ding, Hui Jia, Bo Jiang, Zhiguo Zhang, Chuanlang Zhan, Shenggui He, Qibing Pei, Yongfang Li, Yunqi Liu and Jiannian Yao Polym. Chem. 2012, 3, 2170-2177.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.

Reversible addition–fragmentation chain transfer (RAFT) polymerization was used to generate well-defined pH-responsive biofunctional polymers as potential ‘smart’ gene delivery systems. A series of five poly(dimethylamino ethyl methacrylate-co-cholesteryl methacrylate) P(DMAEMA-co-CMA) statistical copolymers, with similar molecular weights and varying cholesterol content, were prepared. The syntheses, compositions and molecular weight distributions for P(DMAEMA-co-CMA) were monitored by nuclear magnetic resonance (NMR), solid-state NMR and gel permeation chromatography (GPC) evidencing well-defined polymeric structures with narrow polydispersities. Aqueous solution properties of the copolymers were investigated using turbidimetry and light scattering to determine hydrodynamic diameters and zeta potentials associated with the phase transition behaviour of P(DMAEMA-co-CMA) copolymers. UV-Visible spectroscopy was used to investigate the pH-responsive behaviour of copolymers. Hydrodynamic radii were measured in the range 10–30 nm (pH, temperature dependent) by dynamic light scattering (DLS). Charge studies indicated that P(DMAEMA-co-CMA) polymers have an overall cationic charge, mediated by pH. Potentiometric studies revealed that the buffering capacity and pK_a values of polymers were dependent on cholesterol content as well as on cationic charge. The buffering capacity increased with increasing charge ratio, overall demonstrating transitions in the pH endosomal region for all five copolymeric structures. Cell viability assay showed that the copolymers displayed increasing cytotoxicity with decreasing number of cholesterol moieties. These preliminary results show the potential of these well-defined P(DMAEMA-co-CMA) polymers as in vitro siRNA delivery agents.

Synthesis, self-assembly and stimuli responsive properties of cholesterol conjugated polymers by Sema Sevimli,  Sharon Sagnella,  Maria Kavallaris,  Volga Bulmus and Thomas P. Davis Polym. Chem. 2012, 3, 2057-2069.

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.

Fast and scalable production of hyperbranched polythioether-ynes was achieved by applying sequential click chemistry (SCC) via couple-monomer methodology (CMM). As a typical example, thiol-halogen click-like reaction employing strong base, KOH and thiol-yne click reaction via UV irradiation were used for precursor preparation and polymerization, respectively. Two series of hyperbranched polythioether-ynes employing two kinds of di-thiols with different reactivity have been prepared within 10 h and characterized with ¹H NMR spectroscopy and gel permeation chromatography. The hyperbranched polymers (HPs) derived from 1,6-hexanedithiol reached high weight-average molecular weight (M_w) of 230500, high weight-average degree of polymerization (DP_w) of 1224 and high degree of branching (DB) of 0.82–0.68. Postmodification of abundant alkyne terminal groups afford HPs with a greatly enhanced DB of 0.96. Heat-initiated polymerization was also attempted. The present study clearly demonstrates the robustness of application of SCC technique in the CMM strategy for fast, scalable preparation of multifunctional HPs.

Fast and scalable production of hyperbranched polythioether-ynes by a combination of thiol-halogen click-like coupling and thiol-yne click polymerization by Jin Han, Bo Zhao, Aijin Tang, Yanqin Gao and Chao Gao Polym. Chem., 2012, 3, 1918-1925

To keep up-to-date with all the latest research, sign up for the journal’s e-alerts or RSS feeds or follow Polymer Chemistryon Twitter or Facebook.