Highly Stable and Stretchable Conductive Films through Thermal‐Radiation‐Assisted Metal Encapsulation

Abstract

Stretchable conductors are the basic building blocks of advanced flexible electronic devices, such as flexible display, skin-like sensors, stretchable batteries, soft actuators and so forth. [1][2][3][4][5][6][7][8][9][10] They are used in a vast number of soft and stretchable devices developed in recent years, including biointerfacing electrodes, [11][12][13][14][15] transistors, [16][17][18] mechanical sensors, [19][20][21][22] energy devices [23][24][25][26] and many more. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] To meet most application requirements, stretchable conductors need to remain conductive under tensile strain of more than 100%, and even more importantly, to show stable performance in terms of interfacial adhesion between conductive metal film and the supporting polymer substrate.[1] Current methods to achieve stretchable conductors generally fall into two categories. One involves a structural design strategy, where the conducting material is designed with specific structures/topographies including serpentines, [46][47][48][49][50][51][52] wrinkles, [53,54] meshes, [55][56][57][58] and microcracks. [59][60][61][62][63] The other strategy relies on intrinsic stretchability of Stretchable conductors are the basic units of advanced flexible electronic devices, such as skin-like sensors, stretchable batteries and soft actuators. Current fabrication strategies are mainly focused on the stretchability of the conductor with less emphasis on the huge mismatch of the conductive material and polymeric substrate, which results in stability issues during long-term use. Thermal-radiation-assisted metal encapsulation is reported to construct an interlocking layer between polydimethylsiloxane (PDMS) and gold by employing a semipolymerized PDMS substrate to encapsulate the gold clusters/atoms during thermal deposition. The stability of the stretchable conductor is significantly enhanced based on the interlocking effect of metal and polymer, with high interfacial adhesion (>2 MPa) and cyclic stability (>10 000 cycles). Also, the conductor exhibits superior properties such as high stretchability (>130%) and large active surface area (>5:1 effective surface area/geometrical area). It is noted that this method can be easily used to fabricate such a stretchable conductor in a wafer-scale format through a one-step process. As a proof of concept, both long-term implantation in an animal model to monitor intramuscular electric signals and on human skin for detection of biosignals are demonstrated. This design approach brings about a new perspective on the exploration of stretchable conductors for biomedical applications.

Scalable Manufacturing of Free‐Standing, Strong Ti3C2Tx MXene Films with Outstanding Conductivity

“…The scalable processing of nanomaterials into free‐standing films that possess high electrical conductivity and high mechanical properties is critical for enabling diverse applications including those in the area of flexible electronics, such as supercapacitors, [ 1,2 ] electromagnetic interference (EMI) shielding, [ 3 ] sensors, [ 4 ] and actuators. [ 5 ] To produce highly conducting and mechanically strong films from functional nanomaterials, one of the key challenges is to find nanomaterials with inherently high strength and electrical conductivity.…”

An On‐Skin Electrode with Anti‐Epidermal‐Surface‐Lipid Function Based on a Zwitterionic Polymer Brush

“…Therefore, the deposition of gold layer was performed on top of semi‐cured PDMS precursor to acquire Au/PDMS films with strong adhesion between the two layers. [ 46 ] The digital photograph in Figure a shows the as‐prepared PMPC‐grafted electrode. Scanning electron microscopy (SEM) imaging reveals the morphology of the electrode surface (Figure 2b).…”

“…Such wrinkled structure with the interlocking layer between gold and PDMS contributes to the high conductivity, stretchability and strong adhesion between gold and PDMS. [ 46 ] The typical thickness of the PDMS substrate was in the range of 300–400 µm, which can be customized according to the requirement of different flexibility. The thickness of the gold layer was typically 400–600 nm (Figure S1, Supporting Information).…”

In Situ Dynamic Manipulation of Graphene Strain Sensor with Drastically Sensing Performance Enhancement

“…[ 7–10 ] The easy slip between the nanosheets due to their weak vdW interaction force provides the possibility for the study of micromechanical deformation of electronic devices and sensors. Various sensors based on graphene sliding theory [ 11–13 ] with good properties have been proposed. The sliding process of graphene sheets can be divided into two parts: overlap stage and separation stage.…”