Fabrication of a Miniature Paper-Based Electroosmotic Actuator

PDMS-based films with 14 wt% carbon black were formed with varying amounts of hexane (Sigma-Aldrich) to determine the effect of the solvent on electrical resistance. Five formulations were prepared with hexane at 0, 100, 150, 200, and 300% by weight, relative to the pre-polymer. Without hexane, the suspension was a thick paste that had to be applied by doctor blading; with hexane, the suspensions could be cast. These films were poured to a thickness 1 mm, although as they dried the samples with higher hexane fractions were thinner because the volatile hexane escaped. Four films of each concentration were formed on glass slides; 5 g of each mixture was deposited on the glass, and cured in a conventional oven for 2 hours at 65 C, at which time they were dry to the touch.