Multi-nuclear (1H, 2H, and 19F) magnetic resonance spectroscopy techniques as functions of temperature and pressure were applied to the study of selectively deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMIM TFSA) ionic liquid isotopologues and related ionic liquids. For EMIM TFSA, temperature-dependent 2H T1 data indicate stronger electric field gradients in the alkyl chain region compared to the imidazolium ring. Most significantly, the pressure dependences of the EMIM and TFSA self-diffusion coefficients revealed that the displacements of the cations and anions are independent, with diffusion of the TFSA anions being slowed much more by increasing pressure than for the EMIM cations, as shown by their respective activation volumes (28.8 ± 2.5 cm3/mol for TFSA vs. 14.6 ± 1.3 cm3/mol for EMIM). Increasing pressure may lower the mobility of the TFSA anion by hindering its interconversion between trans and cis conformers, a process that is coupled to diffusion according to published molecular dynamics simulations. Measured activation volumes (ΔV‡) for ion self-diffusion in EMIM bis(fluoromethylsulfonyl)amide and EMIM tetrafluoroborate support this hypothesis. In addition, 2H T1 data suggests increased ordering with increasing pressure, with two T1 regimes observed for the MD3 and D2 isotopologues between 0.1–100 and 100–250 MPa respectively. The activation volumes for T1 were 21 and 25 (0–100 MPa) and 11 and 12 (100–250 MPa) cm3/mol for the MD3 and D2 isotopologues, respectively.

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The curvature of VO 2-coated silicon microcantilevers was measured as the temperature was cycled through the coating's insulator-to-metal transition ͑IMT͒, which drives the curvature change mainly through the strain generated during this reversible structural transformation. The films were grown by pulsed laser deposition ͑PLD͒ on heated substrates. Cantilever tip displacement was measured for a 130 m long cantilever as the temperature was changed by recording the deflection of a laser beam, and the curvature change and estimated film stress were calculated from this data. A change in curvature of over 2000 m −1 was observed through the narrow temperature range of the IMT, with a maximum rate of ϳ485 m −1 per degree. Estimated recoverable stress was ϳ1 GPa through the transition region. These results suggest applications in actuator devices with reduced dimensions, including submicron lengths, multifunctional capabilities, and possibly with higher operational frequencies than other thermally actuated devices.