Photolithographic patterning of cellulose: a versatile dual-tone photoresist for advanced applications.

Archim Wolfberger,Stefan Spirk,Jakob Herka,Alexander Fian,Barbara Stadlober,Thomas Griesser,Volker Schmidt,Rupert Kargl,Andreas Petritz

doi:10.1007/s10570-014-0471-4

Abstract

In many areas of science and technology, patterned films and surfaces play a key role in engineering and development of advanced materials. Here, we present a versatile toolbox that provides an easy patterning method for cellulose thin films by means of photolithography and enzymatic digestion. A patterned UV-illumination of trimethylsilyl cellulose thin films containing small amounts of a photo acid generator leads to a desilylation reaction and thus to the formation of cellulose in the irradiated areas. Depending on the conditions of development, either negative and positive type cellulose structures can be obtained, offering lateral resolutions down to the single-digit micro meter range by means of contact photolithography. In order to highlight the potential of this material for advanced patterning techniques, cellulose structures with sub-µm resolution are fabricated by means of two-photon absorption lithography. Moreover, these photochemically structured cellulose thin films are successfully implemented as dielectric layers in prototype organic thin film transistors. Such photopatternable dielectric layers are crucial for the realization of electrical interconnects for demanding organic device architectures.Electronic supplementary materialThe online version of this article (doi:10.1007/s10570-014-0471-4) contains supplementary material, which is available to authorized users.

Highlights

Cellulose, as the most abundant biopolymer on earth and major component of green plants features a set of properties which can hardly be found in any other single material (Klemm et al 2005)
UV-exposure of a trimethylsilyl cellulose (TMSC)/ N-hydroxynaphthalimide triflate (NHNA) blend yields triflic acid as the main photoproduct, which subsequently causes a cleavage of the trimethylsilyl (TMS) groups, resulting in a conversion of TMSC to cellulose as depicted in Scheme 1
The FTIR spectrum before UV-illumination shows a weak signal at 3,490 cm-1, which can be assigned to residual hydroxyl moieties stemming from an incomplete silylation of the hydroxyl moieties as expected for TMSC with a degree of substitution (DSSi) of 2.8, which was used for this study

Summary

Introduction

As the most abundant biopolymer on earth and major component of green plants features a set of properties which can hardly be found in any other single material (Klemm et al 2005). A patterned UV-illumination of trimethylsilyl cellulose thin films containing small amounts of a photo acid generator leads to a desilylation reaction and to the formation of cellulose in the irradiated areas.

Results

Conclusion