Preparation And Applications Of Graphene-Polymer Composite Hydrogels

Since graphene is a type of two-dimensional carbon materials with excellent mechanical,electrical,thermal,and optical properties,the efficient preparation of graphene macroscopic assemblies is of particular significance in the potentially large-scale application of graphene sheets.Conventional preparation methods of graphene macroscopic assemblie s need strict conditions and once formed,the assemblies can't be edited,reshaped or recycled.In this thesis,inspired by the biomineralization process,a feasible approach of shapeable,multi-manipulatable,and recyclable composite hydrogel consisting of graphene oxide/poly?acrylic acid?/amorphous calcium carbonate was designed.The hydrogels could be functionalized to meet a variety of specific application requirements?e.g.,conductive composites,sensing materials,water treatment materials?.Graphene materials were introduced into the biomimetic mineralized hydrogel system to prepare composite hydrogels at room temperature with a cross-linking network structure formed during the preparation process.The hydrogels were stretchable,malleable,self-healable,and easy to process in the wet state,while tough and rigid in the dried state.In addition,these two states could be readily switched by adjusting the water content,which showed the advantage of recyclability and could be used for 3D printing to form varied architectures.Graphene-polymer composite hydrogels were used as sensing materials and showed good editability and processability,and could be fabricated into stretchable strain sensors of various structures?sandwich structures,fibrous structures,self-supporting structures,etc.?.The developed sensors could be attached on different types of surfaces?e.g.,flat,cambered?and work well both in air and under water in detecting various biosignals,including crawling,undulatory locomotion,and human body motion.A graphene-polymer based hybrid coagulant was realized by forming double-network hydrogel through bioinspired crosslinking during the coagulation-flocculation process.When applied to water treatment,the hybrid coagulant could precipitate multiple pollutants?e.g.,dyes,heavy metal ions,and nanoparticles?simultaneously at room temperature to achieve the purification of wastewater.By introducing functional components?e.g.,magnetic Fe₃O₄?,hydrogel composite materials were obtained and used as electrodes for functional devices including supercapacitors and actuators.The methods proposed in this thesis made full use of the advantages of each component of the composite hydrogel and endowed it with new properties.The preparation method was simple,efficient and environmentally friendly,and c ould be extended to other materials for the versatile macroscopic assembly,which was low-cost,efficient,and convenient for broad applications.