A series of imidazolium-based bis(trifluoromethylsulfonyl)imide [NTf 2 ] poly(ionic liquid)s (PILs) were prepared by conducting the solventless thiol-ene 'click' photopolymerization of bisallylimidazolium [NTf 2 ] and pentaerythritol tetrakis(3-mercaptopropionate) (PTMP). The thiol:ene molar ratio was varied in order to examine changes in the thermal, mechanical and conductive properties of the resulting polymer networks. The 1.0:2.0 thiol-ene PIL network exhibited the highest glass transition temperature (T g of-5.0 °C) and storage modulus (E′ of 9.24 MPa at 100 °C) values. Temperature-dependent ionic conductivities were found to rely on both the T g /crosslink density as well as the IL content, with the highest ionic conductivity observed for the 1.0:3.0 thiol-ene PIL network (1.42 x 10-5 S/cm at 25 °C). Application of Vogel-Fulcher-Tammann and Williams-Landel-Ferry theories revealed the impact of both T g /crosslink density and free ion concentration on temperature-dependent conductivity data, and indicated lower free volumes and fragilities for the thiol-ene networks relative to other non-network PILs.

The Marangoni effect describes fluid flow near an interface in response to a surface tension gradient. Here, we demonstrate that the Marangoni effect is the underlying mechanism for flow driven feature formation in an azobenzene-containing polymer film; features formed in azobenzene-containing polymers are often referred to as surface relief gratings or SRGs. An amorphous poly(4-(acryloyloxyhexyloxy)-4′pentylazobenzene) was synthesized and studied as a model polymer.To isolate the surface tension driven flow from the surface tension pattern inscription step, the surface tension gradient was preprogrammed via photoisomerization of azobenzene in a glassy polymer film without forming topographical features. Subsequently, the latent image was developed in the absence of light by annealing above the glass transition temperature where the polymer is a liquid. The polymer flow direction was controlled with precision by inducing different surface tension changes in the exposed regions, in accordance with expectation based on the Marangoni effect. Finally, the height of the formed features decreased upon extensive thermal annealing due to capillary leveling with two distinct rates. A scaling analysis revealed that those rates originated from dissimilar capillary velocities associated with different azobenzene isomers.