Tunable Flexoelectricity of Elastomers

Abstract

Stretchable materials are expected in next-generation devices as examples of soft electronics and wearable healthcare. Elastomers are stretchable and well-applied in various electromechanical applications as substrate and functional materials. Elastomers are believed to have substantial electromechanical response of flexoelectricity, due to their large deformation range and hence large strain gradient capability. Flexoelectricity is an electromechanical coupling effect in dielectrics, describing the linear relation between its strain gradient and its induced electric polarization. In this work, we propose a phenomenological model to study the flexoelectricity of elastomers, where cross-linking density is the key. The flexoelectric coefficient is increased by enlarging the cross-linking density of the elastomer. This model is experimentally verified by measuring transverse flexoelectric response of two typical elastomers. This work shows a fundamental understanding on tunable flexoelectricity of elastomers, and opens up possibilities in material designs for flexoelectric-based applications with elastomers.

Flexoelectric enhanced film for an ultrahigh tunable piezoelectric-like effect

“…We prepare SYLGARD 184-silica composites with four curing ratios (12 : 1, 15 : 1, 18 : 1 and 20 : 1) with corresponding mesh sizes (Table S2, ESI †). Dense crosslinkers stiffen the material with smaller meshes, while sparse crosslinkers soften the SYLGARD 184 with larger meshes 33 (Fig. 2C(i)).…”

“…S1A, ESI †). 29,33 When subjected to a non-uniform deformation (such as bending), equivalent centers of positive and negative charge separate, giving a flexoelectric polarization (Fig. 1A).…”

“…In this work, we propose a flexoelectric enhanced elastomer-based film (FEEF) to systematically characterize a tunable electromechanical performance by demonstrating an ultrahigh piezoelectric-like effect. Based on the flexoelectric mechanism of elastomers in our previous work, 33 spherical nanoparticles (NPs) are immobilized into elastomer networks, engaging a local strain gradient due to size mismatching. Pre-designed strain-gradient-induced polarization is generated under inhomogeneous deformation (Fig.…”

Flexible Nanogenerators based on Enhanced Flexoelectricity in Hausmannite Membranes

“…However, the flexoelectric effect has been studied in only a handful of materials, including ceramic ferroelectrics 14,15,16 , liquid crystals 17 and polymers (elastomers, PVDF) 18,19 . As the magnitude of strain gradient is inversely proportional to the relaxation length, flexoelectric effects increase in lower dimensional materials, making them a natural choice for flexible nanogenerators 20,21,22 .…”

Theoretical Insight into High‐Efficiency Triple‐Junction Tandem Solar Cells via the Band Engineering of Antimony Chalcogenides

“…The growing demand for renewable and sustainable energy requires the development of cost-effective, stable, and efficient solar cells. [1,2] Consequently, a diverse range of photoactive materials, such as CdTe, [3,4] Cu(In 1Àx Ga x )Se 2 , [5,6] Sb 2 (S 1Àx Se x ) 3 , [7][8][9] and organic-inorganic hybrid perovskites, [10][11][12][13] have been used as solar cell materials, which have achieved impressive power conversion efficiencies (PCEs). Sb 2 (S 1Àx Se x ) 3 exhibits advantages, such as a high absorption coefficient, suitable bandgap, abundant raw materials, low toxicity, and easy processability.…”