Application Of Self-assembled?Three-dimensional (3D) And Functional Graphene Aerogels

Graphene,a two-dimensional monolayer sheet of sp²-bonded carbon atoms,has attracted increasing attention in recent years due to its extraordinary mechanical?1.1 TPa?,electrical(106 S cm^-1),thermal(5300 W m^-1 K^-1)properties,and large specific surface area(2600 m² g^-1),high transparency?97.7%?,stable structures.In this thesis,based on the graphene material,we foucs on the self-assembly and polymer-mediated three-dimensional?3D?graphene arogels,and explore the application of graphene in superelastic graphene foam,strain/pressure sensors,actuators,solar desalination and water clean.The main research contents and results are as follows:In the former work,3D polymer/graphene aerogels have been prepared by using of the freezing-directed assembly of graphene and thermal annealing under the assistance of surfactant,which can solve the poor dispersion and compatibility of polymer within graphene matrix.The as-prepared 3D macroporous polymer/graphene aerogels exhibit lightweight,superelastivity?80%strain?,high strength?80 kPa?and excellent electromechanical performance with stable cyclic resilient property and sensitive resistance response,indicating the promising candidate in the application of actuators,elastic conductors,strain/pressure sensors and wearable devices.In the second work,a rationally assembled of polystyrene/graphene capsule-like framework?PS/G-CF?has been successfully fabricated by using a self-assembly strategy.The as-prepared PS/G-CF possesses capsule-like structure,which can sustain large-strain deformations of 95%and compressive stress of 165 kPa,superior to most of the commercial polymer foams,indicating the rubber-like behaviors.As expected,PS/G-CFs can be used as pressure-sensitive materials which exhibit high sensitivity of ca.1.83 kPa^-1 in the low pressure regime from 0.95 to 495 Pa.Moreover,the superhydrophobic structure with a high adhesion to water droplets allows the PS/G-CF to transfer water droplets from a sticky superhydrophobic surface to another one.The versatile and elastic PS/G-CF demonstrated here can also be used as advanced materials in various practical applications including sensors,actuators,liquid transportation and materials used for self-cleaning.In the third work,a scalable fabrication of vertically aligned graphene sheet membrane?VA-GSM?for efficient solar steam generation of clean water has been reported in our work.The O₂-plasma-treated VA-GSM exhibits hydrophilic surfaces,outstanding solar absorption,excellent photothermal transduction,and the highly vertically aligned graphene sheets membrane provides tunable micrometer-scale channels for water to escape.The solar thermal efficiency of VA-GSM is up to ca.90.6%under four sun,superior to most of the previous reports.Based-on the efficient solar thermal generation and stability of VA-GSM,the water clean of seawater,dense acid,alkali solutions,heavy metals in sewage water are realized,and the rejection of ion is up to 99.1%.Compared with other technologies of clean water,such as nanofiltration membrane,reverse osmosis,and electrodialysis,the VA-GSM used in solar steam of clean water is low-cost,high rejection of ions and low operating pressures.