A conductive ternary network of a highly stretchable AgNWs/AgNPs conductor based on a polydopamine-modified polyurethane sponge

Abstract

A highly stretchable silver nanowires/silver nanoparticles (AgNWs/AgNPs) conductor based on a polydopamine (PDA) modified three dimensional polyurethane (PU) sponge was fabricated. The PU sponge skeleton was first modified by PDA to improve adhesion to the conductive nanomaterials. The conductive micro-network was fabricated by dip-coating of the PDA modified PU sponge into the solution of AgNWs, and AgNPs were further sputtered onto its surface to improve conductivity, resulting in a conductive ternary network structure. The resistance of the PDA-PU-AgNW-Ag-PDMS stretchable conductor decreased obviously with bending or stretching cycles initially, and then remained stable even up to 1000 cycles. The composites exhibit high electrical conductivity (exceeding 27.78 S cm À1 ) and excellent electromechanical stability under high tensile strain (50%) owing to the combined effects from the ternary network. The significant electromechanical properties were also demonstrated by a simple stretchable circuit composed of a light-emitting diode (LED) and the stretchable conductor during bending, twisting or stretching. Scheme 1 (a) Schematic illustration of the fabrication of PDA-PU-AgNW-Ag-PDMS stretchable conductor; (b) pictures of PU sponge before (yellow) and after (black) PDA-modification; (c) dip coating process of AgNWs absorbing on the surface of PDA-PU sponge. 62906 | RSC Adv., 2015, 5, 62905-62912 This journal is

Revisit to three-dimensional percolation theory: Accurate analysis for highly stretchable conductive composite materials

“…If there is directional anisotropy in the Poisson’s ratios or reorganization of composite due to the deformation, strain-dependent percolation threshold must be appropriately adjusted. Several researches have mentioned possibility of these effects 31 32 33 and verified them with the experimental results 15 27 34 . In previous research 15 , the strain-dependent percolation threshold was only described by tensile strain.…”

A New Class of Electronic Devices Based on Flexible Porous Substrates

“…Almost all metals, alloys, and ceramic materials can be prepared as targets, and multi‐target co‐sputtering can deposit alloys in precise and constant proportions under appropriate conditions. For example, metals (i.e., Ag, Au, and Cr) have been sputtered on PU sponge, electrospun PVA nanofilm, and porous LCP substrate to produce conductors [ 156 ] and sensors. [ 133 , 134 ] In addition, alloys (i.e., Bi 2 Te 3 ) [ 68 ] and metallic oxide (i.e., Tin‐doped indium oxide) [ 135 ] have been sputtered onto paper to make high‐performance thermoelectric materials and solar cell electrodes, respectively.…”

Three-dimensional highly conductive silver nanowires sponges based on cotton-templated porous structures for stretchable conductors

“…15 However, surface modications of polymer sponges are always needed to increase the adhesion between conductive nanomaterials and polymer bers, where Ni foam should be etched to obtain the porous conductive network. 8,13,15,17,18 Thus the fabrication processes are always complicated. It remains challenging to simply constructing these unique 3D conductive structures into stretchable conductors, which impedes our effort in further exploring their practical ways.…”

“…3,[10][11][12] In order to construct those 3D architectures, polymer sponges (e.g., polyurethane (PU), poly(dimethylsiloxane) (PDMS)) and Ni foam have been used as the skeleton. [13][14][15] Stretchable conductors containing PU-AgNWs or PU-CuAg sponges as the shape deformation structure have been investigated, showing remarkable electrical and mechanical capability. 8,13,16 3D exible graphene/PDMS composite using Ni foam as template has also been reported.…”

“…[13][14][15] Stretchable conductors containing PU-AgNWs or PU-CuAg sponges as the shape deformation structure have been investigated, showing remarkable electrical and mechanical capability. 8,13,16 3D exible graphene/PDMS composite using Ni foam as template has also been reported. 15 However, surface modications of polymer sponges are always needed to increase the adhesion between conductive nanomaterials and polymer bers, where Ni foam should be etched to obtain the porous conductive network.…”