Study On The Thermal Performance Of The Polymer-based Composite Material Interface

The polymer-based composite material interface has unique nano-structure and composition at the interface,which leads to very different physical properties compared to bulk materials.This thesis mainly studies the photothermal conversion performance of the polymer-based composite material and interfacial thermal conductance.As a clean energy source,solar energy is widely used in different industries,including solar power generation and seawater desalination.This study focuses on using photothermal conversion materials to efficiently absorb solar energy and convert it into thermal energy.And we used the localized heating effect proposed by our group to limit thermal energy at gas-liquid surface to heat the water at the surface efficiently.In this way,high temperature steam can be generated rapidly.In this paper,a reduced graphene oxide/polytetrafluoroethylene porous composite film(rGO/PTFE)is used as a photothermal conversion material.The interfacial evaporation system relies on the rapid localized heating of the floating rGO/PTFE composite film under sunlight,which promotes the water evaporation at the interface.A new sterilization method was invented by combining the composite film and interface evaporation system.This newly developed steam sterilization process produces high temperature steam(>100 ° C)under one atmosphere compared to conventional solar autoclaves.Therefore,no complicated design is required to withstand high pressure steam.Both chemical and biological sterilization indicators are used to demonstrate the success of the sterilization performance of the device.The reusability,thermal stability and ease to manufacture of the new method offer a possibility of manufacturing inexpensive and efficient sterilization equipment in areas lack of electricity but with sufficient sunlight.At the same time,since the heat conduction at the material interface has a great influence on the thermal energy utilization efficiency,the thermal conductivity of the interface material is also studied.Different from the traditional method of filling the thermal conductive fillers to prepare the thermal interface materials,this study improves the thermal conductivity of the materials by changing arrangement and structure of the fillers.For example,constructing a three-dimensional heat conduction network in the materials.There are several advantages: 1)higher thermal conductivity in the case of the same material filler fraction;2)better mechanical performance;3)more cost-effective due to less filler fraction.The thermal conductivity of the material can be greatly improved by using the methods mentioned in this paper.Improving the heat dissipation of electronic devices requires not only improving the thermal conductivity of the material,but also reducing the interface thermal resistance and contact thermal resistance,which is the key to improve the heat dissipation performance of the material.Therefore,after improving the thermal conductivity of the material,we also change the chemical properties of the material interface to reduce the thermal resistance of the interface and study the mechanism of the material interface heat transfer.