Smart Adhesive Patches of Antibacterial Performance Based on Polydopamine-Modified Ga Liquid Metal Nanodroplets

Patches have been widely used in medical and healthcare, motion detection, and other fields. Patches are required to possess strong adhesive forces to keep them effectively adhered to the skin during use and to be removed from the skin with relative ease after usage. Moreover, a large number of bacteria will proliferate at the interface between the patch and the skin, when the patch is used for lengthy durations, which is harmful to human health. Hence, there is an increasing demand for patches with combined switchable adhesions and excellent antibacterial performances. Inspired by the natural adhesive performance of snail slime in wet (liquid) and dry (solid) states, smart Ga liquid metal nanodroplet-based polymer patch (GxPP, x = 10, 30, 50) with switchable adhesion properties were prepared by incorporating polydimethylsiloxane (PDMS) into polydopamine (PDA)-modified Ga nanodroplets (PDA-Ga). Since the melting point of Ga is 29.8 °C, solid Ga melts to the liquid state at temperatures above 29.8 °C, and this significantly decreases the modulus of GxPP, resulting in significantly decreased adhesive strength of GxPP. The adhesion of G30PP decreased from 40.4 to 22.1 kPa. In addition to this obvious change in the adhesion properties of GxPP, the unique antibacterial performances of Ga imparted GxPP with excellent antibacterial effects. Compared with the PDMS, the antibacterial rates of G30PP against Escherichia coli and Staphylococcus aureus were 98 and 99%, respectively. The excellent antibacterial performance and smart switchable adhesion properties of GxPP revealed its high application prospects in the field of wearable flexible skin electronics.