Photolabile and thermally labile polymers as templates and for surface patterning

Abstract

The successful selective metal deposition using a photolabile polymer consisting of a diazosulfonate side chain group has been reported. In addition to 20 mol% diazosulfonate monomer the terpolymer contains 5 mol% of a silane compound, which is necessary for the covalent anchoring of the film onto the substrate. Furthermore, films were prepared using photolabile polymers containing protected amines onto glass and silicon substrates. These films are suitable for imagewise structuring by UV‐light and laser irradiation, and nanoelements like DNA strands could be attached individually in further steps. These polymeric amines with similar structure like the diazosulfonate terpolymers were synthesized by free radical polymerization of three monomer units which are methyl methacrylate (MMA) (spacer), 3‐(trimethoxysilyl)propylmethacrylate (anchoring group) and N‐(N‐nitroveratryloxycarbonyl‐aminopropyl)‐methacrylamide (photolabile compound). The anchoring groups were varied to enable covalent attachment of the polymers, for example, onto gold substrates. Azosulfonates, sulfonate esters, and both protected amines and carboxylic acid groups were used as thermally labile or photolabile functionalities. Selective deprotection using heat or light could be varied. Finally block copolymers based on orthogonally protected hydroxystyrenes could be prepared by controlled radical polymerization. A highly ordered nanostructure could be realized in thin films of these polymers exhibiting strong changes using heat or light treatment. Copyright © 2006 John Wiley & Sons, Ltd.

Preparation of a Water-Based Photoreactive Azosulphonate-Doped Poly(Vinyl Alcohol) and the Investigation of Its UV Response

“…UV–Vis spectroscopy is appropriate to investigate UV-induced decomposition of the azo dye in the doped PVA films. As the electron density of the aromatic ring is altered by the cleavage of the azo group, the absorption at 227 nm is diminished and shifted towards lower wavelengths for both azo dyes [26,30,38]. The second absorption maximum at 282 nm (attributed to the π–π* transition) decreases as well.…”

“…The UV-induced decomposition leads to the formation of nitrogen gas, showing no dependence on the chemical environment [23,26,28]. Today, photolabile and thermally low molecular aromatic azo compounds are employed in the field of photoresist materials, laser ablation and recording materials [26,29,30].…”

Protein diffusion from microwells with contrasting hydrogel domains

“…Imidazole can be delivered using a lid gel, as previously described in single-cell electrophoretic assays 6,36,42 . The Ni-His-imidazole release scheme gives short “switching” periods (seconds as compared to minutes or hours), appreciable release efficiency, and adequate spatial control for delivery to microwells, as compared to protein-PA conjugations, 46–48 photo-labile polymers, 49–51 caged particles, 52 photo-activatable probes, 53 drug-releasing nanogels, 54 photo-assembly and photo-cleavable microcapsules, 55 photo-controlled release micelles, 56 protein-protein conjugations, and click chemistry. We use the median measured fluid film thickness of 2 μ m [Fig.…”

Selective Nsp2‐ and Csp2‐ Photografting of Au‐Surface by Aryldiazonium Salts and Arylazo Sulfonates

“…In the latter case, functionalization occurs upon visible light irradiation and under photocatalyst‐free conditions, thanks to the peculiar properties of the N 2 SO 2 R moiety as dyedauxiliary group, that imparts both color and photoreactivity to the substrate [18] . Among arylazo derivatives, arylazo sulfonates, that can be smoothly obtained in discrete yields from the corresponding anilines [19,20] have received sustained interest in the last decades, in view of their applications as visible light photocleavable surfactants, in photoresponsive polymers as well as in organic synthesis [21,22] . The photodecomposition of such derivatives has been investigated in details, pointing out the generation of an aryl radical intermediate [23] …”

“…[18] Among arylazo derivatives, arylazo sulfonates, that can be smoothly obtained in discrete yields from the corresponding anilines [19,20] have received sustained interest in the last decades, in view of their applications as visible light photocleavable surfactants, in photoresponsive polymers as well as in organic synthesis. [21,22] The photodecomposition of such derivatives has been investigated in details, pointing out the generation of an aryl radical intermediate. [23] Our research is deeply focused on the visible light functionalization of surfaces and, in view of these premises, in this paper, we report the unprecedented photografting of gold surfaces by a set of differently substituted arylazo sulfonate sodium salts (ArÀ N=NÀ SO 3 Na, 1 a-e, Scheme 1) to provide strongly bonded organic films.…”