Photosensitive polynorbornene containing the benzyl thiocyanate group—Synthesis and patterning

In this paper, we report the synthesis of a new polymer based on polynorbornene containing the photosensitive benzyl thiocyanate group. The monomer (±)-endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid-bis-(4-thiocyanatomethyl)benzyl ester (2) was prepared from (4-thiocyanatomethyl)benzyl alcohol (1) and (±)-endo,exo-bicyclo[2.2.1]hept-5-ene-2,3-dicarbonyl dichloride as starting materials. Compound 2 was polymerised via ring opening metathesis polymerisation using the Grubbs type initiator [RuCl2(H2IMes)(3-bromo-pyridine)2(CHPh)] providing a photoreactive polymer. The photoreactions of the low molecular compounds as well as of the polymer were investigated by FT-IR spectroscopy. The benzyl thiocyanate group undergoes photoisomerisation to the reactive benzyl isothiocyanate group when exposed to UV-light. Upon a post-modification process with gaseous propylamine, the isothiocyanate group is selectively transformed to the corresponding thiourea derivative. We show that these processes allow patterning of thin films of this polymer by lithographic techniques.

A new photosensitive polynorbornene containing the benzyl thiocyanate group was synthesised by ring opening metathesis polymerisation. Upon illumination with UV-light, the benzyl thiocyanate group undergoes a photoisomerisation to the benzyl isothiocyanate group that can selectively bind amines to form thiourea compounds. In combination with lithographic techniques, this process was used to obtain patterned polymer films. Figure optionsDownload as PowerPoint slide