Preparation Of Attractive Pickering Emulsion Gel-Templated Porous Materials And Application In Solar Interfacial Evaporation

The shortage of fresh water resources is a serious global problem in today’s world.With the increase of population and the rapid development of society,the problem of shortage of fresh water resources is becoming more and more serious.Interfacial solar water evaporation technology has become a feasible solution to the shortage of fresh water resources.Achieving high-efficiency solar water evaporation through proper design of the materials and structures of interfacial solar evaporators becomes a great challenge.Here,we developed a method to fabricate interfacial porous solar vaporizers using Pickering emulsion gels as templates.We first prepared polymeric porous materials by attractive Pickering emulsion gel-template method,and through hydrophilic modification and surface modification,an interfacial solar evaporator was fabricated.The evaporator has excellent solar light absorption performance,excellent thermal insulation performance and good water transmission performance.It provides new design ideas for the research and industrialization of seawater sewage desalination technology.（1）We prepared spherical and Janus polymer nanoparticles for stabilization of Pickering emulsion gels by nanoflash precipitation.Shellac spherical nanoparticles are first prepared,and the prepared nanoparticles have many advantages,including regular shape,narrow particle size distribution,good dispersibility in water,and controllable particle size.Second,shellac/PLA Janus nanoparticles were prepared.Janus nanoparticles have two hemispheres with different compositions.In addition,the prepared Janus nanoparticles have narrow particle size distribution,controllable particle size,designable morphology,and good dispersibility in water.And,due to the certain amphiphilicity of nanoparticles,the prepared spherical and Janus nanoparticles can be used as surfactants to prepare Pickering emulsions.（2）We prepared Pickering emulsion gels stabilized using nanoparticles and telechelic polymers as surfactants.And we designed a method to prepare porous polymer materials using the Pickering emulsion gel as a template.Nanoparticles and telechelic polymers were adsorbed on the oil-water interface as surfactants to stabilize the emulsion,and a gel network was formed in the oil phase due to the electrostatic interaction between telechelic polymers and nanoparticles.Finally,through photocuring,a polymer porous material is formed.The prepared polymer porous material has interconnected pores inside,which can be used for water transportation during solar water evaporation;the porosity is high and can be adjusted;the thermal insulation performance is good,and the thermal conductivity is 0.039 W·m^-1·K^-1;good mechanical properties;low density,so it can float on the water.Therefore,the polymeric porous materials prepared by the Pickering emulsion-gel template method are suitable for the preparation of interfacial solar evaporators.（3）By optimizing the polymer porous material,an interface-type porous solar evaporator was fabricated.Based on the polymer porous material,the porous material is first modified by hydrolysis,and then the polypyrrole coating is modified on the surface of the porous material by chemical vapor deposition to improve its solar light absorption performance.The obtained solar evaporator has a solar absorption rate of 97%.Under one solar irradiation,the water evaporation rate is 1.16 kg·m^-2·h^-1,and the solar energy conversion rate is 73.1%.