Highly Stretchable Conductors Integrated with a Conductive Carbon Nanotube/Graphene Network and 3D Porous Poly(dimethylsiloxane)

Abstract

wileyonlinelibrary.comdiffi culty of uniformly dispersing both CNTs and graphene in polymer matrices and the high-performance demands of electrical conductivity without severe deterioration during stretching. First, because of the high aspect ratio and strong π-π interactions among carbon nano-materials, CNTs tend to bundle and aggregate, and graphene sheets are easy to stack in the matrices. [11][12][13] These processes would all have an adverse impact on the electrical performance of the SCMs. Second, partial breaks and cracks in the conductive networks of matrices are familiar occurrences when the SCMs are stretched to an extremely large strain, for example, 50%. [ 14 ] Therefore, the stretching range will be limited to maintain the excellent electrical performance of SCMs for practical applications.A large number of studies are targeted to addressing these limitations. [15][16][17][18] One attractive and effi cient method to improve the distribution and dispersion of these carbon nano-materials in SCMs is to construct their three-dimensional (3D) structures in advance and then impregnate them within the polymer. [ 23 ] Nevertheless, the commonly used 3D network preparation methods (e.g., organic sol-gel polymerization, [19][20][21] chemical and hydrothermal reduction, [ 22,23 ] and chemical vapor deposition [ 24,25 ] are complex, expensive and time consuming. Therefore, although these structures impart the SCMs with high electrical conductivity while maintaining a low nanofi ller loading, the large-scale manufacturing of CNTs and/or graphene 3D networks is still largely restricted. Moreover, the electrical conductivities of these 3D carbon nano-material-based polymer composites generally exhibit gradual decreases with increasing strains, [ 16,17 ] thereby resulting in signifi cantly reduced conductivities under large strains. For example, in our previous work, the conductivity of a CNT/graphene aerogel/poly(dimethylsiloxane) (PDMS) fi lm exhibited a ≈30% decrease under 30% strain, [ 16 ] and a graphene foam/PDMS composite also revealed a 30% decrease under 50% strain. [ 13 ] This phenomenon is due to cracking of the conductive network under stretching, which would be more prominent under large deformations. Regarding this point, J. Park et al. provided a new design opportunity for obtaining high electrical conductivity performance from SCMs under large strains from the perspective of the polymer substrate. [ 18 ] Their specially designed porous PDMS exhibited a signifi cantly Here, a novel and facile method is reported for manufacturing a new stretchable conductive material that integrates a hybrid three dimensional (3D) carbon nanotube (CNT)/reduced graphene oxide (rGO) network with a porous poly(dimethylsiloxane) (p-PDMS) elastomer (pPCG). This reciprocal architecture not only alleviates the aggregation of carbon nanofi llers but also signifi cantly improves the conductivity of pPCG under large strains. Consequently, the pPCG exhibits high electrical conductivity with a low nanofi ller loading (27 S m −1 wi...

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

“…8,9 The shape deformation and elongation of 3D conductive structures can transfer the stress without decay in conductivity under stretching to a certain extent. 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.…”

Shrinkage induced stretchable micro-wrinkled reduced graphene oxide composite with recoverable conductivity

“…However, the high resistance ($6 · 10 4 X with the highest graphene content) restricts its application in strain sensor rather than stretchable conductors [9]. In the area of graphene based stretchable conductors, which have the same or a higher level of conductivity, the fatigue resistance property has only been tested for less than 100 stretching-release cycles [13,25,30,32]. This lifecycle test is important but has not been investigated in detail by others.…”

“…Porous structures were investigated in this regard, such as graphene/polymer hydrogels [19][20][21], foams [22][23][24] and networks [25], which were constructed either by coating graphene onto porous polymeric matrices, or by incorporating polymer into 3D graphene foams and networks. Extraordinary mechanical flexibility has been demonstrated by hundreds of compressive or bending tests, but achieving a real stretchability is still quite challenging for these porous graphene structures.…”

“…Extraordinary mechanical flexibility has been demonstrated by hundreds of compressive or bending tests, but achieving a real stretchability is still quite challenging for these porous graphene structures. Chen et al [25] reported a conductive carbon nanotube/graphene network which can be stretched up to 80% elongation. Although 100 cycles of stretching and releasing test at 50% strain could be achieved, this is far from the requirement for the application of stretchable conductors.…”

“…Although wrinkled structure with high stretchability can be formed by this pre-stretching and releasing method, weak adhesion between graphene and substrate may lead to delaminated buckles and could not tolerate a series of stretching and release cycles [30]. Moreover, the tolerance to fatigue is still not well documented in the area of graphene based stretchable conductors, where the existing studies showed so far that the electrical conductivity can remain stable for only up to 100 stretching-release cycles [13,25,30,32]. Therefore, graphene based stretchable conductors with both continuously electrical conductivity and high fatigue resistance require further development.…”