Soft gels with high toughness have drawn tremendous attention recently due to their potential applications in flexible electronic fields. The miniaturization and high-power density of electronic devices require soft gels with both high toughness and low thermal resistance; however, it is difficult to achieve these properties simultaneously. Herein, a simple design strategy is reported for constructing soft (high stretchability of 6.91 and low Young's modulus of 340 kPa), tough (4741.48 J m −2 ) and thermal conductive (low thermal resistance of 0.14 cm 2 K W −1 , under 10 psi pressure) polydimethylsiloxane/aluminum composite gel. This is realized by precisely lengthening polymer strands between the chemical cross-linked points and controlling the aluminum content in the composite gels. The symbiosis of this combination involves: lengthening the polymer strands facilitates its unfolding to increase the softness and intrinsic toughness; the thermally conductive spherical aluminum enables low thermal resistance and increases the intrinsic toughness and stress dissipation. By utilizing this gel as a thermal interface material, effective heat dissipation is demonstrated in electronic devices operating under high-power conditions over numerous cycles. These results demonstrate the application potential of composite gels in meeting the performance maintenance and heat dissipation, which are needed for modern electronic devices.
Yupeng Lin,Hong He,Qun Huang,Fengping An,Hongbo Song
Low-temperature soluble and soft gelation (LT-SG) pectin belonging to special gum is an important food additive. Flash extraction optimization of pectin from passion fruit ( Passiflora edulis f. flavicarpa ) peel at low temperature (50 °C) by response surface methodology and LT-SG properties was investigated in the present study. Under the optimized conditions of a rotation speed of 5000 r/min, extraction time of 9 min, and the liquid–solid ratio of 42:1 mL/g, the pectin yield was 7.52%. The DE value of 57.02% indicated it was high methoxyl pectin, which easily dissolved at a low temperature (70 °C). Gel texture analysis revealed that the soft gelation properties were depended on the sucrose concentration and pH in the pectin solution. Both adding sucrose and decreasing pH refined gel network structure, as results, the gel texture was strengthened.
Haiyuan Yuan,Zupeng Liu,Jundong Song,Soichiro Okamura,John H. Xin,Ming Xue,Titao Jing
Stretchable materials are the foundation of dielectric actuators (DEAs) for artificial muscle. However, the inadequate dielectric constant of stretchable materials has always greatly limited the performance of artificial muscle. Recently, soft fillers have been proposed to improve the dielectric property and preserve the stretchability for softness, aiming to avoid the stiffening effect of traditional rigid fillers. As composites, an amount of interfacial region is generated, which remarkably affects composites’ performance from dielectrics to mechanics. Herein, we demonstrate that the size effect, interfacial binding, and compatibility have a great impact on soft filler doped composites. Particularly, according to the liquid characteristics of soft fillers, we explore an interfacial modification method using surfactants. Composite breakdown strength is thus enhanced 2.2-fold from that in the control group due to the reduction of mismatch between fillers and matrix. Moreover, surfactants alleviate the well-known stiffening effect in small fillers. The area strain of the composites reaches 10.3 ± 0.4% at a low electric field of 7 MV/m, and a soft micropump is successfully assembled. These findings demonstrate a unique and combined interfacial influence of soft filler doped elastomer, which promotes the advancements of the dielectric elastomer artificial muscle.
危险品化学品经营许可证（带存储）