Softened double-layer octopus-like adhesive with high adaptability for enhanced dynamic dry and wet adhesion

Abstract

Robust and reversible adhesion at complex interfaces in dry and wet environments is considered an important technology in various applications, such as smart adhesive materials, soft adhesive robots, medical gripping devices, and skin-attachable electronics. For applications attached to the human body, adhesive material is expected to display conformally stable adhesion to rough, dry or wet soft surfaces and maintain adhesion under various movements and stresses. Herein, we propose a double-layered adhesive patch with an octopus inspired architecture (d-OIA) coated with a soft elastomer exhibiting enhanced dynamic adhesive performance. Our double-layered adhesive patch demonstrated enhanced adhesion in the pulling direction against dry and rough underwater surfaces. The soft elastomer coated on the elastic octopus-inspired patterns enabled a high degree of adaptability towards rough surfaces. This adhesive patch can maintain a vacuum state in the chamber through conformal contact, even with rough skin where bending and stretching occur frequently owing to movement. We demonstrated practical applications for healthcare monitoring by detecting electrocardiograms (ECG) and electromyograms (EMG) signals with dynamic motion in dry and even sweaty conditions without significant noise. Based on the features in this study, the proposed stretchable adhesive patch can be used as a promising approach for emerging wearable electronics, e-skin, soft robotics, and their systems.