Photothermal effect of graphene/polymer smart nanocomposites under NIR stimuli

Many studies have shown that a low mass loading graphene nanosheets (GNSs) in a polymer matrix can provide the nanocomposite with high photothermal conversion efficiency in the near-infrared (NIR) region. However, how to accurately control the photothermal effect of graphene/polymer smart nanocomposites is still a key to its application in biomedicine, micromechanical systems and other fields. Aiming to describe the photothermal effect and indicate the photothermal conversion process, a generalized driving force induced photothermal conversion is introduced based on an energy balance relation modified by Maxwell effective medium theory. The effects of GNSs' size and mass concentration, light intensity of NIR irradiation and film thickness of GNSs/polymer nanocomposites on the photothermal conversion are all discussed in this paper. Some critical values (such as GNSs' size and mass concentration, GNSs/polymer nanocomposites film thickness) of the photothermal conversion are predicted, and their influence mechanisms on photothermal conversion are also clarified.