For the stretchable electrode, strong interface adhesion is the primary guarantee for long service life, and the maximization of the tensile limit with remarkable electrical stability can expand the scope of its use. Here, a cost-effective strategy is proposed to fabricate a high-adhesion stretchable electrode. By modifying dopamine and functionalized silane on a polydimethylsiloxane (PDMS) substrate in sequence before the electroless deposition process, super-high adhesion up to 3.1 MPa is achieved between the PDMS substrate and silver layer, and the electrode exhibits extraordinary conductivity of 4.0 × 107 S/m. This process is also suitable for other common flexible substrates and metals. Moreover, inspired by the micro-/nanostructure on the surface of lotus leaf, a biomimetic elastomeric micropore film with a uniformly distributed micropore is fabricated by the one-step soft lithography replication process. The electrode exhibits a large tensile limit exceeding 70% uniaxial tensile and superior electrical stability from 6.3 to 11.5 Ω under 20% uniaxial tensile for more than 10 000 cycles. This study seeks a promising method to manufacture stretchable electrodes with high adhesion, large tensile limit, and excellent electrical stability, showing great potential to detect various biological signals including joint movement, surface electromyography, and so forth.
Bin Yang,Qinting Chen,Mengya Ding,Yang Pan,Peng Zhang,Shuqing Wang,Jiasheng Qian,Jibin Miao,Ru Xia,Peng Chen,You Shi,Youlei Tu
Polyvinylidene fluoride (PVDF) films were prepared via thermally induced phase separation (TIPS) using diphenyl carbonate as the diluter in an attempt to disclose the competitive relationship between crystal growth and droplet growth during phase separation process. By varying the quenching temperature different temperature gradient fields were established, which were theoretically evaluated via enthalpy transformation method. The effects of polymer concentration and quenching temperature on evolution of hierarchical morphologies in TIPS films were systematically investigated. According to the morphological characteristics, the cross-sectional morphology of the films with lower polymer concentration ( Φ P = 25%) could be divided into three layers; while that of higher polymer concentration counterpart ( Φ P = 55%) only presented a bi-layered structure. The reason for this could be ascribed to the effect of cooling rate on both crystal growth and droplet growth during TIPS process, which further determined the formation of the hierarchical structure in microporous films. With an increasing quenching temperature, both pore size and porosity of PVDF films increased, accompanied by an improvement on both thermal stability and dynamic mechanical thermal property. The present study could insightfully supply a facile route to fabricate structure-controllable microporous films of crystalline polymers via an appropriate regulation of the TIPS quenching parameters. Graphical Based upon the phase diagram of polyvinylidene fluoride (PVDF)/diphenyl carbonate (DPC) system, the effects of polymer concentration and quenching temperature on the morphologies in thermally induced phase separation (TIPS) films are quantitatively established. TIPS films with lower (below monotectic point) and higher (above monotectic point) polymer concentrations present three-layered and bi-layered hierarchical structures, respectively, primarily originating from the competition between crystal growth and droplet growth during the phase separation.