No abstract

Four monomers based on 4-ethynylbenzoic acid have been synthesized, one of those featuring an activated ester. With the metathesis catalytic system WCl 6 /Ph 4 Sn, these acetylenic monomers could successfully be polymerized yielding conjugated polymers with molecular weights of around 10,000 to 15,000 g/mol and molecular weight distributions M w / M n 2.1. Also the copolymerization of phenylacetylene or methyl 4-ethynylbenzoate with pentafluorophenyl 4-ethynylbenzoate as reactive unit was conducted. Polymer analogous reactions of the reactive polymers and copolymers with amines have been investigated and it was found that poly(pentafluoro-phenyl 4-ethynylbenzoate) featured a significant reactivity, such that reactions proceeded quantitatively even with aromatic amines. Moreover the UV-Vis spectra of the activated ester based polymer before and after conversion with aliphatic amines showed a change, indicating an effect on the conjugated backbone of the polymers. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: [211][212][213][214][215][216][217][218][219][220][221][222][223][224] 2011

Substituted polyphenylacetylenes featuring reactive pentafluorophenyl (PFP) ester moieties are synthesized. Parts of the reactive PFP groups are then converted with a mono ortho-nitrobenzyl-protected diamine in variable ratios. Thin films are prepared from these copolymers and irradiated with UV light (λ = 365 nm), resulting in crosslinking of the irradiated areas and hence enabling a photopatterning. We found that during the photocrosslinking process, the excess of PFP ester moieties is stable and remained intact, enabling a subsequent post-polymerization modification step with amines. Noteworthy, this subsequent modification with amines results in a dramatically shift in the UV-vis absorption spectra, rendering these patterned conjugated polymer films ideal candidates for optical sensors.

The grafting of poly(hydroxyethylmethacrylate) on polymeric porous membranes via atom transfer radical polymerization (ATRP) and subsequent modification with a photo-responsive spiropyran derivative is described. This method leads to photo-responsive membranes with desirable properties such as light-controlled permeability changes, exceptional photo-stability and repeatability of the photo-responsive switching. Conventional track etched polyester membranes were first treated with plasma polymer coating introducing anchoring groups, which allowed the attachment of ATRP-initiator molecules on the membrane surface. Surface initiated ARGET–ATRP of hydroxyethylmethacrylate (where ARGET stands for activator regenerated by electron transfer) leads to a membrane covered with a polymer layer, whereas the controlled polymerization procedure allows good control over the thickness of the polymer layer in respect to the polymerization conditions. Therefore, the final permeability of the membranes could be tailored by choice of pore diameter of the initial membranes, applied monomer concentration or polymerization time. Moreover a remarkable switch in permeability (more than 1000%) upon irradiation with UV-light could be achieved. These properties enable possible applications in the field of transdermal drug delivery, filtration, or sensing.