Study On Photothermal Conversion And Actuation Behaviors Of Graphene/polymer Nanocomposites

Because of its excellent physical and chemical properties,as well as its strong absorption of near-infrared light and photothermal conversion,graphene can be used as a photothermal filler to effectively improve the light absorption and photothermal conversion properties of composite materials.In particular,its large specific surface area makes it easy for graphene to combine with the polymer matrix to form a new type of composite material bearing the function of photothermal conversion.Such a material has broad application prospects in minimally invasive treatments such as photothermal therapy,photothermal imaging,drug or gene delivery and in intelligent-driven controlling fields,including intelligent robots,artificial muscles,and nanopositioners.Currently,most of research on the photothermal conversion and driving properties of graphene-polymer-based nanocomposites mainly focuses on their practical application.Scholars have conducted experiments to analyze the thermodynamic response and the driven action of those composite materials under near-infrared light irradiation.However,less attention is paid on the influence of graphene concentration,size,interface microstructure and other characteristics on photothermal conversion and driving response behavior.For this reason,it is difficult to achieve precise regulation,which has become the main problem that restricts its successful practical application in the fields of biomedicine and intelligent control.To this end,this paper mainly focuses on the theoretical and numerical analysis of the photothermal conversion and driving behavior of graphene-polymer-based nanocomposites under near-infrared light irradiation.The main research work is divided into the following four parts:1)research was carried out on the equivalent electrical conductivity and dielectric properties of graphene-polymer-based nanocomposites.In order to explore the electrical conductivity and dielectric properties of graphene-polymer-based nanocomposites under near-infrared light irradiation,the photoconductive properties of graphene are introduced in this paper.According to effective medium theories such as Maxwell-Garnett Theory and Bruggeman Theory,the current study confirms the equivalent electrical conductivity and dielectric properties of graphene-polymer-based nanocomposites.In the meanwhile,given the interface effect characteristics such as interface tunneling effect and Maxwell-Wagner-Sillars polarization effect,this study obtains the presentation forms of effective electrical conductivity and dielectric properties of the composite materials at high and low frequencies to analyze the graphite structural features of graphene inclusions such as concentration and scale,as well as the effects of light irradiation frequency on the equivalent electrical conductivity and dielectric properties of the composites.This study lays the foundation for further research on photothermal conversion and driving behavior of graphenepolymer-based nanocomposites.2)research was carried out on the effective mechanical properties of graphenepolymer-based nanocomposites.Based on the Eshelby Equivalent Inclusion Theory and mesoscopic homogenization methods such as the Mori-Tanaka method,the current study establishes the quantitative relationship between the effective stiffness tensor of the composite material and the properties,graphene concentration,graphene size and other factors of each component material.In addition,given the effect of interfacial adhesion,the theoretical characterization forms of equivalent Young’s modulus and equivalent thermal expansion coefficient of composites are established to analyze the influence of the concentration and size of graphene filling phase and the characteristics of interfacial phase on the equivalent mechanical properties of such composites.It provides a theoretical basis for further research on the driving mechanical response behavior of graphene-polymer-based nanocomposites under near-infrared light irradiation.3)combining the characterization of the equivalent electrical conductivity and dielectric properties of graphene-polymer-based nanocomposites,theoretical aspects of the photothermal conversion behavior of such composites under near-infrared light irradiation was investigated.Based on Maxwell’s Electromagnetic Field Theory,the quantitative characterization relationship between the absorption coefficient for nearinfrared light waves of this type of composite materials and electrical conductivity and dielectric constant is established.Based on the energy balance equation,Newton’s law of cooling and other related theories,theoretical model of photothermal conversion of graphene-polymer nanocomposites was established to analyze the effects of nearinfrared light irradiation time and irradiation power,graphene filling concentration and geometry,composite thickness,and interface effects such as interface tunneling and MWS polarization on thermal transformation behavior of composite materials.4)research was done on theoretical modeling and numerical analysis of the photothermal-driven mechanical response behavior of graphene-polymer-based nanocomposites.Combining the above-mentioned theoretical analysis models with the related theories of thermal stress analysis of multilayer thin film structures,a photothermal driving theoretical model is established to analyze the influence of interface effects such as interface adhesion effect,interface tunneling and MWS polarization on the photothermal conversion behavior.At the same time,the effects of interface effect,near-infrared light irradiation time and irradiation power,graphene filling concentration and scale,composite thickness and other parameters on the photothermal driven mechanical response behavior of composites.