Self-Exfoliation of Flake Graphite for Bioinspired Compositing with Aramid Nanofiber toward Integration of Mechanical and Thermoconductive Properties

Abstract

Highlights A self-grinding exfoliation strategy that depends on mutual shear friction between flake graphite particles is successfully developed to prepare pristine graphene with largely enhanced yield and productivity. Bioinspired assembly of pristine graphene nanosheets to an interconnected aramid nanofiber network is achieved by a continuous sol-gel-film transformation strategy and generates a flexible yet highly thermoconductive film. Abstract Flexible yet highly thermoconductive materials are essential for the development of next-generation flexible electronic devices. Herein, we report a bioinspired nanostructured film with the integration of large ductility and high thermal conductivity based on self-exfoliated pristine graphene and three-dimensional aramid nanofiber network. A self-grinding strategy to directly exfoliate flake graphite into few-layer and few-defect pristine graphene is successfully developed through mutual shear friction between graphite particles, generating largely enhanced yield and productivity in comparison to normal liquid-based exfoliation strategies, such as ultrasonication, high-shear mixing and ball milling. Inspired by nacre, a new bioinspired layered structural design model containing three-dimensional nanofiber network is proposed and implemented with an interconnected aramid nanofiber network and high-loading graphene nanosheets by a developed continuous assembly strategy of sol–gel-film transformation. It is revealed that the bioinspired film not only exhibits nacre-like ductile deformation behavior by releasing the hidden length of curved aramid nanofibers, but also possesses good thermal transport ability by directionally conducting heat along pristine graphene nanosheets. Graphical abstract

Programmable and Shape–Color Synchronous Dual-Response Wood with Thermal Stimulus

“…Two-dimensional nonlinear finite element analysis (2D-FEA) simulation (Figure e and Video S1) revealed the toughening mechanism of stabilized crack growth stemming from the highly anisotropic layered structures. During a three-point bending test on a 2D-FEA model, the branches, deflections, and bridged cracks were clearly observed, reminiscent of high-performance natural materials, such as nacre or bone. − The thin vitrimers strips could be pulled out, resulting in friction between adjacent strips, which could lead to dissipating energy loading. Compared with pure vitrimers where the stress concentration occurred around the crack tip, the tortuous crack in SRW and SRW-TC effectively reduced stress concentration, contributing to enhanced fracture toughness (Figure S11).…”

Functional Materials and Innovative Strategies for Wearable Thermal Management Applications

“…For example, materials with high cross-plane thermal conductivity can passively cool the human body temperature by transferring heat from the skin to the external environment [54,[70][71][72][73][74][75][76][77][78][79][80][81][82][83][84]. On the other hand, materials with high in-plane thermal conductivity can effectively spread heat in the lateral direction, which is particularly useful when the skin temperature of a localized region is too high or low [85][86][87][88][89][90][91][92][93][94][95]. Several fabrication methods are available to control the alignment of thermally conductive materials in both the cross-plane and in-plane directions.…”

Application and Development of Smart Thermally Conductive Fiber Materials

“…Furthermore, the emphasis on energy conservation, the rising demand for personal temperature regulation, and the proliferation of wearable electronics and smart textiles have made effective personal thermal management (PTM) a critical area of research [ 11 ]. Consequently, developing thermally conductive materials that offer efficient thermal management has become a key research direction [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. An increasing number of researchers are now focusing on smart thermally conductive fiber materials ( Figure 1 ).…”