Poly(2-nonyl-2-oxazoline) 80 -stat-poly(2-dec-9 1 -enyl-2-oxazoline) 20 and poly(2-dec-9 1 -enyl-2-oxazoline) 100 can be synthesized from the cationic ring-opening polymerization of monomers that can be derived from fatty acids from renewable resources. These (co)poly(2-oxazoline)s can be crosslinked with di-and trifunctional mercapto compounds using the UV-induced thiol-ene reaction. The complex permittivity of the corresponding networks increases with the temperature and decreases with the network density. In a frequency range from 10´2 to 10 6 Hz and at temperatures ranging from´20 to 40˝C, the changes of the real part of the complex permittivity as well as the loss factor can be explained by interfacial polarization within the material. At a temperature of 20˝C and a frequency of 50 Hz, the permittivity of the crosslinked (co)poly(2-oxazoline)s covers a range from 4.29 to 4.97, and the loss factors are in the range from 0.030 to 0.093. The electrical conductivities of these polymer networks span a range from 5ˆ10´1 2 to 8ˆ10´9 S/m, classifying these materials as medium insulators. Notably, the values for the permittivity, loss factor and conductivity of these copoly(2-oxazoline)s are in the same range as for polyamides, and, hence, these copoly(2-oxazoline)-based networks may be referred to as "green" alternatives for polyamides as insulators in electronic applications.

A 2-oxazoline monomer bearing a norbornenyl functionality in the side-chain was prepared from the reaction of 5-norbornene-2-carbonitrile and 2-ethanol amine. This monomer could be successfully polymerized using a 2-oxazolinium-based macroinitiator that was in-situ1 Introduction UV-induced crosslinking is a key strategy for the three-dimensional patterning of structures on substrate surfaces [1]. The patterns, which are preset by masks during illumination, can be reproduced either as positive or as negative image, and the formulations are referred to as positive or negative photoresists. Commonly used positive (negative) resists comprise the DNQ/Novolak system (the SU-8 system and acrylic photoresists) [2][3][4]. Proper adherence of the formulations on the substrates is a key prerequisite for high-resolution reproduction of the patterns.2-Oxazolines are a class of monomers that can be polymerized in living cationic ring-opening polymerizations, yielding (block co-) poly(2-oxazoline)s with targeted properties [5][6][7]. Copoly(2-oxazoline)s bearing linear olefinic side-chains can be used in photoresist formulations: Polymeranalogous crosslinking of poly(2-oxazoline)s in the solid state by thiol-ene reactions has shown to meet the criteria of high yields, high reproducibility, and high resolution [5]. In addition it was shown that the statistical copoly(2-oxazoline)s exhibit good adhesion on various substrates, overcoming the challenges associated with some combinations of substrates and commercially available photoresists.In order to further enhance the tool-box of poly(2-oxazoline)-based materials, this study aimed at the synthesis of a 2-oxazoline monomer bearing olefinic cyclic side-chains. The feasibility of polymeranalogous modifications of the corresponding polymer was proven on the example of UV-induced crosslinking of the olefinic moieties.

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