Polymer Chemistry Blog

Researchers from Clarkson University have synthesised an α-keto ester methacryloylethyl phenylglyoxylate (MEPG), and its homopolymer, and tested their photoinitiation capabilities in a crosslinking monomer resin system.

This resin system contained bis-phenol A-glycidyl methacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA). The CO evolution from the photoinduced decarbonylation led to a significant reduction in the volume shrinkage of the resin upon photocuring with UV light. The addition of an inorganic filler (SiO₂) to the resin did not affect the CO generation and further reduced the volume shrinkage.

Interested to know more? Why not read the full article for free: K. Omrane, J.-J. Feng, R. E. Partch and D. A. Shipp, Polym. Chem., 2011, 2, 1307–1311.

Poly(ethylene glycol) is one of the most frequently used polymers for biomedical applications.

In this review, recent developments in controlled polymerisation techniques – and particularly those they allow alternatives to PEG – are highlighted. Key to the biological application of these techniques is a method by which to improve the properties of polymer therapeutics and several are presented in this review. However, a more comprehensive understanding of the complex interactions of synthetic materials with the numerous biological entities and barriers in the human body is necessary in order fine-tune their therapeutic impact.

Interested to know more? Why not read the full article for free: M. Barz, R. Luxenhofer, R. Zentel and M. J. Vicent, Polym. Chem., 2011, DOI: 10.1039/c0py00406e (Advance Article)

Covalently linked protein–nanogel hybrids (PNHs) have been synthesized using AGET ATRP in an inverse miniemulsion.

A genetically engineered protein, which contained a non-natural amino acid bearing an ATRP initiator, has been used to synthesise protein–nanogel hybrids by electron transfer ATRP in an inverse miniemulsion. This is an appropriate synthetic strategy to covalently, site specifically incorporate green fluorescent proteins into well-defined nanogels. The hybrids are expected to be suitable for potential controlled release applications.

Interested to know more? Why not read the full article for free: S. E. Averick, A. J. D. Magenau, A. Simakova, B. F. Woodman, A. Seong, R. A. Mehl and K. Matyjaszewski, Polym. Chem., 2011, DOI: 10.1039/c1py00050k (Advance Article)

Researchers from Zhejiang University have constructed photo-responsive, biocompatible micelles from amphiphilic diazonaphthoquinone-modified hyperbranched polyphosphates.

HPHEEP–DNQ was synthesised by modification of hydrophilic hyperbranched polyphosphate (HPHEEP) with hydrophobic, light-responsive 2-diazo-1,2-naphthoquinone (DNQ). This polymer could then self-assemble into micelles. Model drug coumarin 102 was encapsulated into these micelles and its controlled release by UV irradiation was confirmed by fluorescence spectroscopy. It was also proved that the micelles had excellent biocompatibility.

Interested to know more? Why not read the full article for free: C. Chen, G. Liu, X. Liu, S. Pang, C. Zhu, L. Lv and J. Ji, Polym. Chem., 2011, DOI: 10.1039/C1PY00094B (Advance Article)

Researchers from Technion–Israel Institute of Technology have studied the kinetics of polymerization under confinement.

Experimental results show that the polymerisation kinetics are different inside a core–shell electrospun nanofibre compared to the bulk. The reaction rate decreases when the mean size of the clusters approaches the size of the internal fibre diameter. This causes the polymerisation reaction to become polychromatic, where the rate of reaction decreases with time.

Interested to know more? Why not read the full article for free: C. S. Reddy, A. Arinstein and E. Zussman, Polym. Chem., 2011, DOI: 10.1039/C0PY00285B (Advance Article)

Researchers from University of Florida have developed the first cathodically colouring yellow-to-transmissive switching electrochromic polymer.

Electrochromic displays require the modulation of three subtractive primary colours (red, yellow and blue or cyan, magenta and yellow) in order to express all of the colours in the spectrum. This work reports the first polymer that is yellow in its neutral state and highly transmissive in its oxidised state. The polymer achieves a 70% transmittance contrast at its absorption maximum and is capable of a full switch in under one second, therefore showing promise as a component of a full multicolour electrochromic device.

Interested to know more? Why not read the full article for free: C. M. Amb, J. A. Kerszulis, E. J. Thompson, A. L. Dyer and J. R. Reynolds, Polym. Chem., 2011, DOI: 10.1039/C0PY00405G (Advance Article)

Collaborative research from Hong Kong, Greece and China has investigated the flow of star polymers through nanopores.

Ultrafiltration of star chains with different lengths and numbers of arms shows that the minimum flow rate at which the chains begin to pass through a nanopore is independent of the arm length, but is strongly affected by the total number of arms and the number that initially enter the pore. These results are expected to influence the design of non-viral polymeric carriers for transporting genes into or through organs, such as the liver or kidneys.

Interested to know more? Why not read the full article for free:  H. Ge, S. Pispas and C. Wu, Polym. Chem., 2011, DOI: 10.1039/C0PY00361A (Advance Article)

Researchers from Princeton University and University of Connecticut have shown that 4,4′-diazidobiphenyl is an efficient photoactivatable crosslinker for polystyrene.

Crosslinking of the core of polystyrene-block-poly(ethylene oxide) copolymer nanoparticles was achieved by encapsulation of small molecule aryl diazides (4,4′-diazidobiphenyl) and subsequent photolysis. Nanoparticles modified in this way showed high thermal stability and have potential to be used as nanobeads for PCR. It was also found that 4,4′-diazidobiphenyl can confer solvent resistance to thin films of polystyrene.

Interested to know more? Why not read the full article for free: Siyan Zhang, Douglas H. Adamson, Robert K. Prud’homme and A. James Link, Polym. Chem., 2011, DOI: 10.1039/C0PY00350F (Advance Article)