Adaptive mechanical behaviors in nature have inspired the development of synthetic adaptive composites, with those responsive to water particularly relevant for biomedical applications. Polymer nanocomposites containing cellulose nanocrystals (CNCs) are prime examples of water-responsive mechanically adaptive materials. Although CNCs are biobased, the matrixes of these composites are exclusively petroleum-based synthetic elastomers, in sharp contrast to their biological counterparts. In this work, we attempted to probe the possibility of using bioderived rubber(s) as the matrix to fabricate CNC-nanocomposite with water-responsive adaptive mechanical behaviors. Specifically, natural rubber (NR) and epoxidized natural rubber (ENR) were used as the composite matrixes. Our results show that the water-responsive sensitivity and reversibility of ENR composites is much more drastic than that of NR composites. This is attributed to the strong CNC–polymer interaction (hydrogen bonding) for ENR, which leads to better filler dispersion and the formation of an extra CNC–polymer network in addition to the CNC–CNC filler network present in the NR composite. The synergistic effect of the dual networks plays a key role in tuning the mechanical properties and water-responsive sensitivity for various potential biomedical applications. Our study further provides guidance to make use of renewable resources to produce high value added water-responsive nanocomposites.Keywords: cellulose nanocrystals (CNCs); dual network; epoxidized natural rubber (ENR); nanocomposites; water-responsive;

•TPU/PLA composites with different phase morphology were prepared.•The toughness of PLA was significantly improved by controlling the morphology of TPU.•The toughening mechanism of TPU/PLA composites with different phase morphology of TPU was studied.•TPU/PLA composites exhibit significantly improved tensile toughness at low TPU content (20 wt%).•The toughening effect of TPU fibers or fiber network is much better than sea-island morphology at the same content.Oriented thermoplastic polyurethane (TPU) fiber and fiber network were first prepared by electrospinning. The as-prepared TPU fiber or fiber network was then pre-fixed in poly(lactic acid) (PLA)/TPU composite to improve the toughness of PLA. For comparison purpose, TPU/PLA composites with sea-island morphology were also prepared by traditional solution blending and mechanical blending. The results show that the toughness of PLA is greatly increased by the special pre-fixed oriented TPU fibers even at a low content, and the toughness is further increased by the TPU fiber network. Our results indicate for the first time that the toughening effect of special TPU fibers or fiber network is much better than that of traditional TPU with sea-island morphology. This study provides guidance to largely improve the toughness of PLA by designing the special phase morphology of TPU.

•Mechanism on morphology development of POE/PP TPVs was deeply proposed.•POE/PP TPVs exhibits smaller rubber nanoparticles/agglomerates than EPDM/PP TPVs.•Higher degree of crosslinking accelerates the formation of rubber nanoparticles.•Higher shear rate and moderate crosslinking rate facilities the phase inversion.Polyolefin elastomer (POE)/polypropylene (PP) thermoplastic vulcanizates (TPVs) is considered to be a better alternative to commercial ethylene-propylene-diene monomer (EPDM)/PP TPVs owing to its better overall performance and low-cost. In this study, we deeply studied the morphology development of POE/PP blends during dynamic vulcanization (DV) and its influencing factors such as the degree of crosslinking, crosslinking rate and shear rate. The results show that POE/PP TPVs exhibits smaller rubber nanoparticles (RNPs) and their agglomerates than that of EPDM/PP TPVs because of the better compatibility between POE and PP. The morphology development during DV of POE/PP TPVs is dominated by the formation and agglomeration of POE RNPs caused by the combined effect of dynamical in-situ crosslinking and the shear-induced break-up of POE phase. Higher degree of crosslinking, higher shear rate and moderate crosslinking rate of POE phase facilitate the rapid formation of smaller RNPs and RNPs agglomerates, and accelerate the occurrence of faster phase inversion. This study provides guidance for the preparation of high performance POE/PP TPVs by controlling the microstructure.Higher degree of crosslinking, higher shear rate and moderate crosslinking rate of POE phase facilitate the rapid formation of smaller RNPs and RNPs agglomerates, and the occurrence of faster phase inversion.Download high-res image (110KB)Download full-size image

Herein, we report an approach to the preparation of a homogeneous styrene–butadiene–styrene triblock copolymer (SBS) dielectric elastomer (DE) with dramatically improved actuated strain by using a photochemical thiol–ene click reaction. The stock SBS was grafted with dipoles (ester groups) to increase the polarizability of SBS. The grafting degree of dipoles on SBS can be controlled by irradiation time to control its electromechanical properties. The grafting degree of modified SBS increases with the increase of irradiation time, and a maximum grafting degree of 81% can be achieved at a radiation time of 40 min. After modification, the phase mixing of PB and PS blocks occurs and the size of PS domains largely decreases, leading to the obvious decrease in the tensile strength and elastic modulus (Y). However, the modified SBS still shows good tensile strength (>3 MPa). More importantly, the dielectric constant (k) largely increases for the modified SBS. The simultaneous increase in k and decrease in Y result in a large increase in electromechanical sensitivity, and thus a large increase in maximum actuated strain and the actuated strain at low electric fields (e.g. 15 kV mm−1). In addition, the modified SBS shows consistently low dielectric loss. Our study provides a simple, effective and controllable chemical method to prepare a homogeneous DE with a high k, large actuated strain at a low electric field, good mechanical strength, easy processibility, and recyclability.

The liquid phase exfoliation (LPE) method, as a cheap, easily scalable, and eco-friendly method, was used to produce defect-free, unoxidized graphene. A surfactant-free technique was used to concentrate the graphene dispersion through stabilization by carbon nanotubes (CNTs) without functionalization. A special kind of aligned CNT bundles, which can be well dissociated into single CNTs in N-methyl-pyrrolidone by sonication, was used and fabricate Gr-CNT hybrid by π - π interaction. A redispersed stable Gr-CNT dispersion at a concentration of 2 mg mL−1 was used for preparing Gr-CNT/thermoplastic polyurethane (TPU) dielectric composite. The results show that the addition of 3.0 vol.% of hybrid improves the dielectric constant of the TPU greatly. As a result, a 10 times increase in electromechanical sensitivity (β) at 1000 Hz and 3.4 times increase in actuated strain at a low electric field (7.5 kV/mm) was achieved. The breakdown strengths of the Gr-CNT/TPU composites with 0.25 vol.% and 1.0 vol.% of hybrid are much higher than that of the pure TPU. As a result, the maximum actuated strain increases greatly from 4.8% for the pure TPU to 7% for the composite with 0.25 vol.% of the hybrid. Meanwhile, the energy density increases from 18 kJ/L for the pure TPU to 25 kJ/L and 48 kJ/L for the composites with 0.25 and 1.0 vol.% of hybrid, respectively.

Thermoplastic vulcanizates (TPVs), as a special class of high-performance thermoplastic elastomers (TPEs), consist of a high content (60–80 wt%) of crosslinked rubber particles as the dispersed phase and a low content of a thermoplastic as the matrix. In this study, inspired by the special microstructure of TPVs, we prepared carbon nanotubes (CNTs)/TPV dielectric elastomer composites with a high dielectric constant (k) and low dielectric loss by constructing a dual network formed by rubber and CNTs. The rubber network was formed by a high content of agglomerates of rubber nanoparticles in the TPVs, which simultaneously promoted the formation of a CNTs network at a low content of CNTs in the matrix, to increase the value of k, and hindered the direct connection of CNTs with one another, to decrease the dielectric loss. As a result, the CNTs/TPV composites simultaneously possessed a high value of k and low dielectric loss. Moreover, the elasticity of the composites was improved by the CNTs because of the nanosprings of CNTs. This study provides a new simple and effective strategy for preparing a high-performance dielectric elastomer with a high value of k, low dielectric loss, good mechanical properties, high elasticity, high processability and easy recyclability.

We studied the microstructure, morphological evolution and the corresponding mechanism, and the properties of bromo-isobutylene-isoprene rubber (BIIR)/polypropylene (PP) thermoplastic vulcanizates (TPVs). Interestingly, a large number of single rubber nanoparticles were observed in the crosslinked BIIR/PP blends, ascribed to the improvement of compatibility between the BIIR and PP with increasing dynamic vulcanization (DV) time, as demonstrated by the increase in interfacial phase thickness and the decrease in the interfacial tension. Most of these single nanoparticles agglomerated as the DV proceeded, leading to the deterioration of the rubber network. Another interesting observation was that the size of rubber agglomerate decreased as the DV proceeded, leading to the strengthening of the rubber network. Importantly, the as-prepared BIIR/PP TPV exhibits good processability, high elasticity and good mechanical property. The relationship between the unique morphology and properties were studied. Our study provides guidance for the preparation of high-performance BIIR/PP TPV for its industrial applications such as medical bottle stoppers.

The dispersion and filler network of fibrillar silicate (FS) in elastomers were studied. The results showed that a good dispersion of FS in matrix during mechanical blending in unvulcanized composites contributed to a strong FS filler network, different from that of traditional reinforcing fillers. Meanwhile, the filler re-aggregation during vulcanization caused by the overlapping and intertwining of FS further strengthened the filler network. The factors including Mooney viscosity and molecular polarity of elastomer, type and amount of silane coupling agents used for filler modification, that may influence the filler network, were studied. Our study helps us to understand the mechanism for the formation of filler network of FS in elastomers and provides guidance for the preparation of high performance FS/elastomer composites.

We report the design and preparation of a separated-structured all-organic dielectric elastomer (DE) with large actuation strain under ultra-low voltage and high mechanical strength. Based on the protonic-conductivity mechanism of gelatin, a novel organic conductive filler with high dielectric constant and low elastic modulus was prepared by mixing gelatin and glycerol (GG). The separated structured DE was prepared by spraying a solution of GG into the multiple layers of thermoplastic polyurethane elastomer (TPU) nonwoven fabric by electrospinning, followed by hot pressing under vacuum. The densely packed TPU nonwoven fabric not only ensures the good mechanical strength of GG/TPU DE, but also separates GG filler and stops the formation of the GG continuous phase, preventing the formation of a conducting path under an exerted electric field. The novel GG filler considerably increases the dielectric constant and decreases the elastic modulus of the GG/TPU DE. As a result, the as-prepared DE exhibits good mechanical strength and 5.2% actuation strain at a very low electric field (0.5 kV mm−1). To the best of our knowledge, the required electric field for the same actuation strain is the lowest compared to other DE reported in the literature. Because all components in this composite are organic and biocompatible, this study offers a new method for preparing a DE with large actuation strain at low electric fields for its application in biological and medical fields, in which a low electric field is required.

Thermoplastic vulcanizates (TPVs) have attracted considerable attention as typical “green” polymers in recent years and have been widely used in industry because they combine the excellent resilience of conventional elastomers and the easy recyclability of thermoplastics. With a new understanding of the formation and agglomeration of the rubber nanoparticles in ethylene propylene diene monomer/polypropylene (EPDM/PP) TPV, we revealed a new mechanism for the morphology evolution of TPV during dynamic vulcanization (DV). The phase inversion in TPV is dominated by the formation and agglomeration of the rubber nanoparticles rather than the elongation and breakup of the cross-linked rubber phase as previously reported. The size of the rubber agglomerates increases with increasing DV time and then remains constant after DV. In addition, we studied the relationship between the cross-linking of the rubber phase, formation and agglomeration of the rubber nanoparticles, and phase inversion and variation of the rubber network during DV. This study provides guidance to control the microstructure of TPV in preparation of high performance TPV products for automobile and electronic applications.Keywords: Atomic force microscopy (AFM); Dynamically vulcanized EPDM/PP blends; Mechanism; Morphology evolution; Phase inversion; Rubber network

•We obtained a good dispersion and alignment of GONS in the TPU matrix.•We improved the dielectric constant by reducing GONS and disrupting hydrogen bonds.•We prepared dielectric elastomer with improved actuated strain at low voltage.Thermally reduced graphene oxide (TRG)/thermoplastic polyurethanes (TPU) dielectric elastomer with high dielectric constant (k), low dielectric loss and greatly improved actuated strain at low electric field was prepared by solution blending followed by in situ thermal reduction. The results showed that a good dispersion and alignment of TRG in the TPU matrix was obtained. The k at 103 Hz was sharply increased from 7 for pure TPU to 1875 for the composite with 2 vol. % of TRG because of the partial restoration of graphite structure and the great increase in dipole polarizability of TPU caused by the disruption of hydrogen bonds of TPU chains. The dielectric loss at 103 Hz of the composite with 2 vol. % of TRG remained low (0.43). Despite of the increase in elastic modulus with the increase in the content of TRG, the great increase in k lead to the great increase in electromechanical sensitivity (β). As a result, a 106 times increase in β at 103 Hz and 17 times increase in actuated strain at low electric field (250 V/mm) were achieved by adding 2.0 vol% of TRG. This study provides a simple and effective method for the improvement of actuated strain at low electric fields through partial reduction of graphene oxide and the disruption of hydrogen bonds in TPU, facilitating the applications of dielectric elastomers in the biological and medical fields, where a low electric field is required.

Dielectric elastomer actuators (DEAs) can lead to surprisingly large deformations by applying an electric field. The biggest challenge for DEAs is to get a large actuated strain at a low electric field. Herein, a novel approach was used to largely improve the actuated strain at a low electric field of a thermoplastic polyurethane (TPU) dielectric elastomer (DE) by introducing polyethylene glycol (PEG) oligomer into the matrix. The dielectric constant (εr) of TPU was obviously increased by adding PEG due to the combined effect of the increase in the interfacial polarization ability of TPU/PEG blends by the ionic conductivity of PEG and the increase in dipole polarization ability of TPU chain segments by the disruption of hydrogen bonds of TPU chains. Meanwhile, the elastic modulus (Y) of TPU was obviously decreased due to the plasticizing effect of PEG on TPU. The simultaneous increase in εr and decrease in Y resulted in a 7500% increase in actuated strain at a low electric field (3 V μm−1) by adding PEG. The actuated strain (5.22% at 3 V μm−1) is considerably higher than that of other DEs at the same electric field reported in the literatures. Our work provides a simple and effective method to largely improve the actuated strain at a low electric field of a DE, facilitating the application of DE in biological and medical fields.

A novel dielectric composite with high dielectric constant (k), low dielectric loss, low elastic modulus and large actuated strain at a low electric field was prepared by a simple, low-cost and efficient method. The graphene oxide nanosheet (GO)-encapsulated carbon nanosphere (GO@CNS) hybrids were fabricated for the first time via π–π interaction and hydrogen bonding interaction by simply mixing the CNS and GO suspension. The assembly of GO@CNS hybrids around rubber latex particles was realized by hydrogen bonding interaction between carboxylated nitrile rubber (XNBR) and GO@CNS hybrids during latex compounding. The thermally reduced GO (RGO)@CNS/XNBR composites were then obtained from GO@CNS/XNBR by vulcanization and in situ thermal reduction, resulting in the formation of a segregated filler network. The results showed that k at 103 Hz obviously increased from 28 for pure XNBR to 400 for the composite with 0.75 vol% of the hybrids because of the formation of a segregated filler network and the increased interfacial polarization ability of the hybrids after in situ partial thermal reduction. Meanwhile, the composite with 0.75 vol% of the hybrids retained low conductivity (10−7 S m−1), resulting in low dielectric loss (<0.65 at 103 Hz). In addition, the elastic modulus only mildly increased with the addition of 0.75 vol% of the hybrids, retaining the good flexibility of the composites. More interestingly, the actuated strain at 7 kV mm−1 obviously increased from 2.69% for pure XNBR to 5.68% for the composite with 0.5 vol% of RGO@CNS, and the actuated strain at a lower electric field (2 kV mm−1) largely increased from 0.23% for pure XNBR to 3.06% for the composite with 0.75 vol% of RGO@CNS, which is much higher than that of other dielectric elastomers reported in previous studies, facilitating the application of the dielectric elastomer in biological and medical fields, where a low electric field is required.

The breakup of the rubber phase in an ethylene–propylene–diene monomer (EPDM)/polypropylene (PP) blend at the early stage of dynamic vulcanization is similar to that in an unvulcanized EPDM/PP blend because of the low crosslink density of the EPDM phase. In this work, the minimum size of the rubber phase in the unvulcanized EPDM/PP blend was first calculated by using the critical breakup law of viscoelastic droplets in a matrix. The calculated results showed that the minimum size of the rubber phase in the unvulcanized blend was in the nanometer scale (25–46 nm), not the micrometer scale as reported in many works. Meanwhile, the actual size of the rubber phase in the thermoplastic vulcanizate (TPV) at both the early stage and the final stage of dynamic vulcanization was observed by using peak force tapping atomic force microscopy (PF-AFM). The results indicated that the EPDM phase indeed broke up into nanoparticles at the early stage of dynamic vulcanization, in good agreement with the calculated results. More interestingly, we first revealed that the micrometer-sized rubber particles commonly observed in TPV were actually the agglomerates of rubber nanoparticles with diameters between 40 and 60 nm. The mechanism for the formation of rubber nanoparticles and their agglomerates during dynamic vulcanization was then discussed. Our work provides guidance to control the microstructure of the rubber phase in TPV to prepare high performance TPV products for a wide range of applications in the automobile and electronic industries.

Thermally expanded graphene nanoplates (TGNPs) were introduced into polydimethylsiloxane (PDMS) matrix by using solution mixing method to obtain TGNPs/PDMS dielectric composites with high dielectric constant (k), low dielectric loss and large actuated strain. The results indicated that the k at 103 Hz was obviously increased from 3.1 for pure PDMS to 18.3 and 89.5 for the composite with 1.6 wt% and 2.0 wt% TGNPs, respectively. Meanwhile, the volume resistivity of all the composites was larger than 109 Ω cm, indicating a low direct current conductance. As a result, the dielectric loss at 103 Hz retained a low value for all the composites. In addition, a significant increase in actuated strain was obtained from 1.4% for pure PDMS to 3.6% with the addition of 2.0 wt% TGNPs under a low electric field (15 V/μm). The mechanism for the largely improved dielectric properties was carefully discussed based on the uniform dispersion of TGNPs in PDMS matrix, the gradual formation of many parallel or serial micro-capacitor structures (low direct current conductance) with the content of TGNPs increasing, and the remained oxygenic groups coated on TGNPs after high temperature thermal exfoliation. Our work provided a simple, low-cost and effective method to prepare high performance dielectric elastomer (DE), facilitating the wide application of DE composites, especially in the biological and medical fields such as biosensors, artificial muscles, and prosthetics.

The effect of in-situ crosslinking of poly (ethylene-co-octene) (POE) rubber phase on the interfacial crystallization of isotactic polypropylene (iPP) in dynamically vulcanized iPP/POE blends was studied. The results showed that in situ crosslinking of POE obviously increased the interfacial crystallization of iPP in the dynamically vulcanized blends, comparing with that of pure iPP and the unvulcanized blend. The interfacial crystallization of iPP was further increased with the increase in crosslink degree. After annealing, the obvious interfacial crystallization was still obtained in the blend with high crosslink degree. Based on the fluctuation assisted nucleation mechanism in solution blended iPP/polyolefin block copolymer (OBC) blends, we proposed for the first time the interfacial crystallization mechanism in dynamically vulcanized blends: the oriented chains of iPP formed by concentration fluctuation at the interface during phase separation or shearing stress during melt mixing can be maintained because of the in situ crosslinking of POE phase, resulting in the enhancement of nucleation density at the iPP/POE interface. Our study proposes a new interfacial crystallization mechanism, and provides guidance for the preparation of high performance thermoplastic vulcanizates (TPVs) product by tailoring the interfacial crystallization of TPVs.

In this work, an elastomeric Fe3O4 nano-particles (NPs)/polybutadiene rubber (BR) composite membrane was prepared by using the combined technique of electrospinning and in-situ crosslinking. The results showed that the saturation magnetization (Ms) and the coercive force (Hc) of the electrospun composite membrane with 5 wt.% Fe3O4 NPs was increased by 21 % and 69 %, respectively, comparing with the membrane prepared by solution casting. This was ascribed to the fine nano-dispersion of Fe3O4 NPs in BR matrix by using the electrospinning and in-situ crosslinking technique because the re-aggregation of Fe3O4 NPs was largely restrained by the fast evaporation of solvent, the confined space of nano/micro-sized fibers and the rapid crosslinking during electrospinning. Our work demonstrated that electrospinning and in-situ crosslinking is a simple and efficient method to improve the dispersion of nanoparticles in an elastomer matrix, and thus prepare high performance elastomeric nanocomposite.

In this work, surface modification of fibrillar silicate (FS) is conducted by using supercritical CO2(sc-CO2) technique. For comparison purpose, conventional modification method is also carried out. The results showed that physical adsorption of the modifier (KH570) on FS surface dominated by using conventional method, whereas chemical adsorption dominated by using sc-CO2 technique. In addition, a more uniform adsorption of the modifier on FS surface is successfully obtained by using sc-CO2 method. This is ascribed to the special gaseous and liquid characteristics of sc-CO2, which can facilitate the diffuse and the full contact of KH570 on the whole surface of FS. The modified FS are then melt blended with ethylene–propylene ethylidene norbornene terpolymer (EPDM) to prepare rubber composites with excellent high temperature performance and good ageing resistance. The results showed that a more uniform dispersion of FS in EPDM matrix and a stronger interfacial interaction between FS and EPDM are successfully achieved by surface modification of FS in sc-CO2, which lead to the obviously enhanced mechanical properties of the composites. Our work demonstrates a better surface modification technique for FS to largely improve the interfacial interaction between FS and EPDM and to obtain a high performance FS/EPDM elastomer composites for its wide application such as transmission belts of automobile.

A novel dielectric composite with high dielectric constant (k), low dielectric loss, low elastic modulus and large actuated strain at a low electric field was prepared by a simple, low-cost and efficient method. The graphene oxide nanosheet (GO)-encapsulated carbon nanosphere (GO@CNS) hybrids were fabricated for the first time via π–π interaction and hydrogen bonding interaction by simply mixing the CNS and GO suspension. The assembly of GO@CNS hybrids around rubber latex particles was realized by hydrogen bonding interaction between carboxylated nitrile rubber (XNBR) and GO@CNS hybrids during latex compounding. The thermally reduced GO (RGO)@CNS/XNBR composites were then obtained from GO@CNS/XNBR by vulcanization and in situ thermal reduction, resulting in the formation of a segregated filler network. The results showed that k at 103 Hz obviously increased from 28 for pure XNBR to 400 for the composite with 0.75 vol% of the hybrids because of the formation of a segregated filler network and the increased interfacial polarization ability of the hybrids after in situ partial thermal reduction. Meanwhile, the composite with 0.75 vol% of the hybrids retained low conductivity (10−7 S m−1), resulting in low dielectric loss (<0.65 at 103 Hz). In addition, the elastic modulus only mildly increased with the addition of 0.75 vol% of the hybrids, retaining the good flexibility of the composites. More interestingly, the actuated strain at 7 kV mm−1 obviously increased from 2.69% for pure XNBR to 5.68% for the composite with 0.5 vol% of RGO@CNS, and the actuated strain at a lower electric field (2 kV mm−1) largely increased from 0.23% for pure XNBR to 3.06% for the composite with 0.75 vol% of RGO@CNS, which is much higher than that of other dielectric elastomers reported in previous studies, facilitating the application of the dielectric elastomer in biological and medical fields, where a low electric field is required.

Dielectric elastomer actuators (DEAs) can lead to surprisingly large deformations by applying an electric field. The biggest challenge for DEAs is to get a large actuated strain at a low electric field. Herein, a novel approach was used to largely improve the actuated strain at a low electric field of a thermoplastic polyurethane (TPU) dielectric elastomer (DE) by introducing polyethylene glycol (PEG) oligomer into the matrix. The dielectric constant (εr) of TPU was obviously increased by adding PEG due to the combined effect of the increase in the interfacial polarization ability of TPU/PEG blends by the ionic conductivity of PEG and the increase in dipole polarization ability of TPU chain segments by the disruption of hydrogen bonds of TPU chains. Meanwhile, the elastic modulus (Y) of TPU was obviously decreased due to the plasticizing effect of PEG on TPU. The simultaneous increase in εr and decrease in Y resulted in a 7500% increase in actuated strain at a low electric field (3 V μm−1) by adding PEG. The actuated strain (5.22% at 3 V μm−1) is considerably higher than that of other DEs at the same electric field reported in the literatures. Our work provides a simple and effective method to largely improve the actuated strain at a low electric field of a DE, facilitating the application of DE in biological and medical fields.

We report the design and preparation of a separated-structured all-organic dielectric elastomer (DE) with large actuation strain under ultra-low voltage and high mechanical strength. Based on the protonic-conductivity mechanism of gelatin, a novel organic conductive filler with high dielectric constant and low elastic modulus was prepared by mixing gelatin and glycerol (GG). The separated structured DE was prepared by spraying a solution of GG into the multiple layers of thermoplastic polyurethane elastomer (TPU) nonwoven fabric by electrospinning, followed by hot pressing under vacuum. The densely packed TPU nonwoven fabric not only ensures the good mechanical strength of GG/TPU DE, but also separates GG filler and stops the formation of the GG continuous phase, preventing the formation of a conducting path under an exerted electric field. The novel GG filler considerably increases the dielectric constant and decreases the elastic modulus of the GG/TPU DE. As a result, the as-prepared DE exhibits good mechanical strength and 5.2% actuation strain at a very low electric field (0.5 kV mm−1). To the best of our knowledge, the required electric field for the same actuation strain is the lowest compared to other DE reported in the literature. Because all components in this composite are organic and biocompatible, this study offers a new method for preparing a DE with large actuation strain at low electric fields for its application in biological and medical fields, in which a low electric field is required.