Preparation And Application Of Graphite Nanoplates-based Thermal Conductive Substrates

Sustainable and smart thermal management in modern wearable electronics are becoming increasingly paramount important driven by improving the reliability and preventing premature failure of electronics.In this work,carbon-based thermal conductive fillers and polymer materials are used as matrix to prepare high thermal conductive composites,which have high thermal conductivity and excellent heat dissipation effect.The preparation and application of graphite nanosheets,sodium carboxymethyl cellulose,polyimide,carbon nanotubes and polyimide were studied.Firstly,we study the development of a new type of nanocomposites based on highly oriented graphite nanoplatelets(GNPs),functional as a thermal substrate with enhanced thermal conductivity and efficient cooling effect via a manufacturable process Firstly,GNP/CMC(Sodium carboxymethyl cellulose)nanocomposite films(GMFs)were fabricated in mass industry available level by gap coating method,in which GNPs were well preferred due to the driving interface wettability and interaction of CMC,resulting in high in-plane thermal conductivity.Then,GNP/CMC thermal plates(GTPs)with enhanced thermal conductivity(～29.5W/(m·K))and a low density(1.14 g cm-3)were produced using as-prepared GMFs and epoxy as fillers and adhesive by lamination and hot pressing method,exhibiting an outstanding heat dissipation on electronic cooling.At 1-3W chip power,the chip temperature on our GTP substrate is 18.9-47.7oC lower than that on traditional polycarbonate(PC)substrate.The obtained boosted thermal conductance of GTPs is primarily attributed to their biomimetic "brick-wall"microstructure with GMFs and epoxy as brick and cement,which is the same as the structure of shell with mineral and protein as brick and cement,respectively.Secondly,in the preparation of graphite nanosheet(GNP)/sodium carboxymethyl cellulose(CMC)composite thermal conductive substrate,the thermosetting epoxy resin acts as the framework of the composite to improve the mechanical properties of the composite.However,there are too many interlaminar adhesives,resulting in thermal resistance,which makes the actual heat dissipation effect worse.By using the self-binding effect of PAA to polyimide(PI),and replacing CMC with PAA solution,the problem of decreasing interlaminar thermal conductivity can be solved.Finally,using the thermal conductivity of carbon nanotubes to improve the thermal conductivity of polyimide matrix and become reinforcing phase to improve its mechanical properties,greatly improving the comprehensive thermal conductivity of the composites.It provides a research basis for thinning and flexibility of the electronic industry in the future and has broad application prospects.