Boosting Sensitivity and Durability of Pressure Sensors Based on Compressible Cu Sponges by Strengthening Adhesion of “Rigid‐Soft” Interfaces

Abstract

The interface adhesion plays a key role between rigid metal and elastomer in compressible and stretchable conductors. However, the poor interfacial adhesion hinders their wide applications. To strengthen the interface adhesion, herein, a combination strategy of structure interlocking and polymer bridging is designed by introducing a method of subsurface‐initiated atom transfer radical polymerization (sSI‐ATRP). This method can make polymer brush root in polydimethylsiloxane (PDMS) subsurface, on this basis, metals further grow from subsurface to surface of PDMS via electroless deposition. As a result, the adhesive strength (≈2.5 MPa) between metal layer and PDMS elastomer is 4 times higher than that made by common polymer modification. As a demonstration, pressure sensor is constructed by using as‐prepared compressible 3D Cu sponge as a top electrode and paper‐based interdigited metal electrode as a bottom electrode. The device sensitivity can reach up to 961.2 kPa−1 and the durability can arrive at 3 000 cycles without degradation. Thus, this proposed interface‐enhancement strategy for rigid‐soft materials can significantly promote the performance of piezoresistive pressure sensors based on 3D conductive sponge. In the future, it would also be expanded to the fabrication of stretchable conductors and extensively applied in other flexible and wearable electronics.

Iron–Gold Galvanic-Assisted Rapid Grafting of Polymer Brushes on n-Silicon for a Triboelectric Nanogenerator

“…Grafting polymer brushes with targeted construction and functionality have been intensively used to realize surface modifications and possessed potentials in biolubrication, − antifouling, , biomedical, and energy engineering. − An appealing strategy for preparing diverse polymer brushes is surface-initiated atom transfer radical polymerization (SI-ATRP or SI-CRP), , including activators regenerated by electron transfer (ARGET) ATRP, photo-ATRP, , electrochemically mediated ATRP (eATRP), − and supplemental activator and reducing agent (SARA) ATRP. − The last mentioned technology deserves special attention because it allows precise control of the chemical composition, structure, and thickness of polymer brushes. − So far, the transition metal catalysts have been extended to Cu, ,,− Fe, ,, Zn, − and Sn since surface-initiated zerovalent metal-mediated controlled radical polymerization (SI-Mt 0 CRP) was proposed. Among them, SI-Fe 0 ATRP was considered one of the best choices for “green” reactions because of the low toxicity, cost-effectiveness, and biocompatibility of iron-based catalysts. , However, the classical iron-based catalytic systems normally show limited monomer suitability, slow polymerization rate, and weak controllability over the polymerization. , …”

High-Sensitivity Wearable Flexible Pressure Sensor Based on MXene and Polyaniline for Human Motion Detection

“…Designing low-cost, high-toughness electrodes or electrode sponge bonding strategies is of great significance. 34 In this work, MXene solution and polyaniline solution were prepared by etching method and chemical oxidation polymerization method, respectively. Then, MXene/PANI was coated on the sponge skeleton by a step-dip coating method, and the flexible strain sensor based on three-dimensional porous structure was prepared.…”

“…On the one hand, it is an expensive conductive silver paste, and on the other hand, it is a common electrode with poor flexibility. Designing low-cost, high-toughness electrodes or electrode sponge bonding strategies is of great significance …”