Integrated Computational Materials, Process and Product Engineering – IC-MPPE 2022

This work presents a multi-stimuli responsive sensor for artificial skin applications. The sensor is responsive to surrounding changes in force, humidity and temperature. The developed design consists of a hydrogel core, responsive to temperature and humidity changes; and a piezoelectric shell for force detection. Swelling of the hydrogel core, in response to humidity and temperature, mechanically strains the piezoelectric shell and generates detectable electric charge. The two materials are combined into core-shell nanorod structures, using state-of-the-art vapor-based deposition techniques. These deposition techniques provide control over material’s mechanical, optical and electrical properties in addition to film’s conformity and uniformity. Moreover, the core-shell nanorods are deposited into a nanostructured UV-curable resin, which allows the fabrication of the embedded core-shell nanorods. 1. Piezoelectric zinc oxide is synthesized using plasma-enhanced atomic layer deposition (PE-ALD).In PE-ALD, substrate temperature defines the deposited film’s crystalline properties. A combination between (100) and (002) crystallographic orientations gives control over zinc oxide’s piezoelectric properties. In this work, piezoelectric zinc oxide layer with combined (100) and (002) preferential orientation is deposited at low temperatures, which is advantageous for when flexible substrates. 2. humidity and temperature responsive hydrogel, Poly-N-vinylcaprolactam (pNVCL), is synthesized using initiated chemical vapor deposition (iCVD). The dry vapor-phase technique gives control over the lower critical solution temperature (LCST), amongst other material properties. 3. The multi-stimuli responsive core-shell nanorods are deposited into nanostructured UV-curable polyurethane acrylate (PUA) resin, with nanoholes having a diameter d = 500 nm, height L = 500 nm and pitch = 1000 nm, achieved using UV nanoimprint lithography (UV-NIL).