Octopus-Inspired Smart Adhesive Pads 

School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City 44919, Korea

Tel.:82-52-217-2532, E-mail: hyunhko@unist.ac.kr

Smart adhesives which stick to and release from a surface on demand have potential

​ applications in skin-attachable wearable devices, smart-printing processes,

medical adhesives, and industrial assembly systems. By mimicking the cavity-pressure-

induced adhesion of octopus suckers, here we demonstrate smart adhesive pads, where

thermo-responsive actuation of a hydrogel layer on elastomeric microcavity pads enables

excellent switchable adhesion in response to a thermal stimulus. The smart adhesive pad

exhibits an adhesive strength of 94 kPa and an adhesion switching ratio of ~293 in response

to temperature change between 22 and 61 °C for repeated cycles. As a proof-of-concept

application, the smart adhesive pads have been employed in the transfer printing of

semiconductor micro- and nanomembranes onto arbitrary substrates to fabricate

heterogeneously integrated semiconductor devices. The smart-printed InGaAs transistors

on Si substrates exhibit an excellent field-effect mobility (~2026 cm²·V^-1s^-1) and on/off

current ratio (~4 × 10³), which are among the best for heterogeneous InGaAs transistors,

demonstrating the high efficiency of our smart-printing technique. The bioinspired smart

adhesive system suggested in this study is also applicable to the heterogeneous integration

of arbitrary micro-/nanoscale objects, which has a great potential in the fabrication of high-

performance transistors and optoelectronic devices on heterogeneous or flexible substrates.

Our smart adhesive pads provide a robust platform for applications in wearable devices,

medical adhesives, and assembly of micro- and macro-scale objects in industrial

manipulation systems.