Direct-Write Fabrication of Cellulose Nano-Structures via Focused Electron Beam Induced Nanosynthesis

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 introduce a new generic technique for the fabrication of polysaccharide nano-structures via focused electron beam induced conversion (FEBIC). For the proof of principle, organosoluble trimethylsilyl-cellulose (TMSC) thin films have been deposited by spin coating on SiO2 / Si and exposed to a nano-sized electron beam. It turns out that in the exposed areas an electron induced desilylation reaction takes place converting soluble TMSC to rather insoluble cellulose. After removal of the unexposed TMSC areas, structured cellulose patterns remain on the surface with FWHM line widths down to 70 nm. Systematic FEBIC parameter sweeps reveal a generally electron dose dependent behavior with three working regimes: incomplete conversion, ideal doses and over exposure. Direct (FT-IR) and indirect chemical analyses (enzymatic degradation) confirmed the cellulosic character of ideally converted areas. These investigations are complemented by a theoretical model which suggests a two-step reaction process by means of TMSC → cellulose and cellulose → non-cellulose material conversion in excellent agreement with experimental data. The extracted, individual reaction rates allowed the derivation of design rules for FEBIC parameters towards highest conversion efficiencies and highest lateral resolution.

Deposition of Cellulose-Based Thin Films on Flexible Substrates

“…The specimen preparation involved embedding of the substrates in epoxy resin, followed by microtomy. The morphology of these slices was then observed in SEM, wherein a complication arises due to the sensitivity of TMSC in an electron beam, which can easily lead to the regeneration of the TMSC, as reported earlier (Figures S3 and S4) [39].…”

Manufacturing Large-scale Materials with Structural Color

“…For machining, a binder is usually added to obtain a pressed object that is robust enough to handle and machine. Takeoka and co-workers recently demonstrated that pressing can be used to create discs that are Further methods from 3D printing of structurally colored cellulose derivative assemblies [26] to nanoscale patterning for color creation via focused electron-beam-induced conversion [83] have proven the wide range of manufacturing potential for structurally colored cellulose-based materials.…”

Ultrathin Films of Cellulose: A Materials Perspective

“…AFM height images of TMSC films treated with an electron beam (A,B,D) and subsequent development with toluene (C) [Reproduced from Ganner et al, 2016 under the terms of the Creative Commons Attribution (CC-BY) license].…”

“…The feature size of the structures was further reduced to the real nanometer regime by a focused ion beam (Ganner et al, 2016). Usually, electron beams harm biopolymers rather fast to create carbon.…”