Home
Resources
Publications
Electron Beam Patterning of Polymerizable Ionic Liquid Films for Application in Photonics

Electron Beam Patterning of Polymerizable Ionic Liquid Films for Application in Photonics

Krzysztof Rola, Adrian Zajac, Maciej Czajkowski, Marta Fiedot-Tobola, Andrea Szpecht, Joanna Cybinska, Marcin Smiglak, Katarzyna Komorowska

Langmuir. 2019 Sep 17;35(37):11968-11978.

PMID: 31442379

Abstract:

Planar photonic components can be fabricated with high resolution by electron beam patterning of polymer thin films on solid substrates such as silicon and glass. However, polymer films are normally formed by spin-coating lithographic resists containing not only polymers but also volatile solvents, which is a serious environmental and health issue. Therefore, we investigate a new type of material for planar structure fabrication (i.e., room-temperature ionic liquids (RTILs) with a polymerizable allyl group) that is electron-beam-curable, solvent-free, and thus potentially interesting for processing materials with weak resistance to solvents. We fabricate planar polymer microstructures by electron beam patterning of RTIL thin films in vacuum, which is possible because of the negligible volatility of ionic liquids. Three different polymerizable ionic liquids {i.e., [Allmim][Cl] (1-allyl-3-methylimidazolium chloride), [Allmim][NTf2] (1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), and [Allmmim][NTf2] (1-allyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide)} are compared in terms of the quality of the fabricated microstructures. We demonstrate that the shape of the more viscous RTIL with the Cl- anion is less distorted during electron-beam-activated polymerization than the shape of the less viscous RTILs with a large NTf2- anion. Furthermore, the surface tension of the NTf2-based ionic liquid decreases significantly with temperature as compared to that of the Cl-based ionic liquid. Thus, we suggest that the thermocapillary effect, that is, the Marangoni flow caused by a temperature gradient, might be responsible for the differences in the shape of the RTIL-derived microstructures. Also, we analyze the chemistry of the electron-beam-activated polymerization of RTIL by the use of Fourier-transform infrared spectroscopy (FTIR) and conclude that because of the disappearance of C═C bonds the free radical polymerization is a probable reaction mechanism. Finally, we show that polymerized microstructures are potentially attractive as planar photonic components because of good optical properties such as a high refractive index.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP655249879	1-Allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide		655249-87-9	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: