Formation and characterization of microcantilevers produced from ionic liquid by electron beam irradiation

Recently, ionic liquids (ILs) have been recognized to have significant potential as precursors or reaction media in nanolithography and MEMS component technologies. In this work, we demonstrate straightforward fabrication of positioned and well-defined microscale structures by electron beam (e-beam) irradiation of two different ILs: 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM TFSI) and 1-(6-hydroxyhexyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM-OH TFSI). The study includes comparison between the compositions and mechanical properties of corresponding e-beam-irradiated ILs. The average Young's moduli of prepared IL microcantilevers measured in beam bending tests were found to be 7.2 ± 0.9 GPa and 3.5 ± 1.3 GPa for HMIM-OH TFSI and HMIM TFSI, respectively. Infrared spectroscopy indicated the formation of polymer in e-beam-irradiated HMIM-OH TFSI, while structures from HMIM TFSI melted in ambient conditions. The presented results showcase the potential IL precursors in microscopic 3-D printing approaches for mechanical elements in MEMS technologies as well as for developing reversibly solidified precursors for lithography.