Novel Aniline Oligomer Based Photo-Thermal Functional Polymers

Photo-thermal conversion polymers have show great importance in many research fields and practical applications.At present,there are two major categories of photothermal conversion polymers,including inorganic photo-thermal nanoparticle polymer composites and organic photo-thermal conversion polymer materials.However,the inorganic photo-thermal nanoparticles suffer from the deficiencies such as difficulty to disperse in the polymer substrates,high-cost,complicated preparation and unstability to light irradiation.As with the organic photo-thermal conversion polymer materials,small molecular light-thermal dyes suffer from decomposing under irradiation,with poor resistance to photo-induced bleaching.And the fluorescence emission reduces the photothermal conversion efficiency;The conductive photo-thermal polymers are with poor solubility and processing performance due to the rigid conjugated structures.All the above deficiencies limit the large-scale practical applications of the existing photothermal conversion polymer materials.In this thesis,we put forword the idea that aniline oligomers can be used as photo-thermal agents and prepared a series of novel photothermal functional polymers.Aniline oligomers are easy to prepare and dissolve in most of solvents,low-cost and with flexible and adjustable functional groups.What is the most important is that aniline oligomers can be introduced into the polymer chains by covalent bonding,achieving a completely uniform dispersion and overcoming the aggregation problem of inorganic nanoparticles.Via reasonable molecular designation,multifunctional and multi-stimuli responsive polymer was prepared.Utilizing the processability of vitrimers and the local,remote and rapid controllable operation of light,actuators with complex 3D structures were prepared.Moreover,we investigated the practical applications of the aniline oligomer-based photo-thermal conversion polymers.The main results of this thesis are:(1)Smart polymer that combines multi-stimuli responsivity with multi-functionality in the same material was prepared.Utilizing the processability of vitrimers and the multiple responsivity of aniline oligomers,the obtained polymer was endowed with heat,light,electricity,pH,redox reagents and metal ions responsivity,as well as shape memory,welding,healing,recycling,electrochromism and metal ions adsorption functionality.This work overcomes the challenges to make a polymer with more than three functionalities or responsivities.(2)By introducing aniline oligomers into liquid crystalline vitrimer,the obtained polymer has excellent photo-thermal effect.It can perform the light-induced functions such as shape memory,welding and healing.Via stretching at temperature above the topology-freezing transition temperature,mono-domain liquid crystalline polymer actuator was obtained,with excellent light-controllable actuation performance and actuation stability.(3)A universal strategy for preparing complex 3D actuators was put forward.Aniline oligomer was introduced into vitrimer based on disulfide exchange reaction.With reasonable molecular designation,a sunlight regulated hygroresponsive bilayer actuator was obtained,which overcomes the critical challenges including reconfiguration,delamination,robust processing and green input energy.Various actuators with complex 3D structures were obtained via patterning,reconfiguration,kirigami or welding techniques.(4)A single-component porous polymer foam with high content of aniline oligomer was prepared via condensation reaction between aniline oligomer and paraformaldehyde.The foam can be used as solar evaporator with an efficiency of 80% at 1 sun,comparable to that of the best graphene-based evaporators.Moreover,it can also be used for seawater desalination and sewage treatment.