Interfacial Coordination Interaction Enables Soft Elastomer Composites High Thermal Conductivity and High Toughness

Abstract

Soft elastomers have attracted wide applications, such as soft electronic devices and soft robotics, due to their ability to undergo large deformation with a small external force. Most elastomers suffer from poor toughness and thermal conductivity, which limits their use. The addition of inorganic fillers can enhance the thermal conductivity and toughness, but it deteriorates the softness (low Young's modulus and high stretchability). Integrating thermal conductivity, toughness, and softness into one elastomer is still a challenge. Here, we report a strategy of interfacial coordination interaction to achieve soft elastomer composites with high thermal conductivity and high toughness. We demonstrate the strategy by using poly(lipoic acid) elastomer and silver-coated aluminum filler as model, where silver−sulfur coordination cross-links are formed at the interface. The resultant elastomer composite shows high streachability (450%), high thermal conductivity (2.35 W m −1 K −1 ), low modulus (321 kPa), and high toughness (3496 J m −2 ), which cannot be achieve in existing elastomers. The time domain thermoreflectance technique demonstrates that the silver−sulfur coordination interaction lowers the interfacial thermal resistance, resulting in enhanced thermal conductivity of the elastomer composites. The excellent softness stems from lower bonding energy of the silver−sulfur coordination cross-links compared with covalent chemical cross-links. The high toughness also benefits from the interfacial silver−sulfur coordination interaction that can dissipate more energy upon deformation. We further demonstrate the potential application of the thermally conductive, tough, and soft elastomer composites for thermal management of chip and soft electronic devices.

Flexible and Stretchable Elastomer Composites Based on Lightweight Liquid Metal Foam Spheres with Pod-like Contacts

“…Since the thermal conductivity of liquid was better than that of solid, the heater containing LMS with L–L contact mode had the highest thermal conductivity of 0.423 W·m –1 ·K –1 , almost 4 times larger than that of the PDMS sample (Figure b). This value also helps the present product to exhibit higher thermal performance in comparison to many previously reported soft-conductive materials. − Next, the heating performance of the heater containing LMS with L–L contact mode was studied. A DC voltage supplier was connected to the two ends of the heater, and an infrared thermal camera was used to monitor the heating process and the corresponding temperature changes.…”

Soft Composite Gels with High Toughness and Low Thermal Resistance through Lengthening Polymer Strands and Controlling Filler

“…C. Tan 2020 [34] 7.14 2.67 75 D. He 2022 [35] 8.51 0.34 Part of the data was deduced from the corresponding formula.…”

A supramolecular approach for converting renewable biomass into functional materials

“…A natural and nontoxic coenzyme, a-thioctic acid (TA), was used to achieve hydrogen bonding with the polar units of biomass, such as carboxylic acid, phenol, and sugar. [33][34][35] Although some TA-involved supramolecular assemblies are soft materials and display relatively poor mechanical properties, [36][37][38] the introduction of natural polymeric biomass significantly improves the mechanical performances of poly[TA-biomass]s. Importantly, supramolecular copolymerization between TA and biomass not only yields bulk poly[TA-biomass]s but also generates reversible and dynamic properties: comprehensive and tough adhesion, thermal processability, impact resistance, recyclability, 3D printing, and antimicrobial activity.…”