Laser-micromachined cellulose acetate adhesive tape as a low-cost smart material

Abstract

An off-the-shelf, moisture-responsive, acetate-backed adhesive tape is investigated as a commercially available smart material for fabricating low-cost, multifunctional, humidity-responsive millimeter-scale structures. Laser ablation is used for cutting and thinning-down the tape to enhance its response. Water-submerged cantilevers show a radius of curvature of 3 mm or lower (for laser-thinned cantilevers). Additionally, their humidity response is a function of the angle between the longitudinal axis of the cantilever and polymer orientation. A cut angled at 80° with respect to this orientation results in a tip rotation of up to 25°, enabling the formation of bending cantilevers with twisting behavior. The tape cantilevers are further functionalized with magnetic nanoparticles and used to create four-finger grippers that close underwater within minutes and can sample 100 μL of liquid. A cyclic humidity monitor is also fabricated using a tape strip that walks unidirectionally on a ratchet-shaped surface upon exposure to humidity variations. © 2013 Wiley Periodicals, Inc.