| Porous ionic polymers(PIPs)is a new type of porous polymer which connects the structural units containing ionic groups by chemical bonds,so that the ionic part is not only attached to the pore wall of the polymer,but also embedded in the pore.An important characteristic of PIPs is that its physical and chemical properties,functional groups and active sites can be adjusted by ion exchange.Moreover,due to its high charge density,high surface area,well-defined porosity and the diversity of synthesis methods,PIPs has potential application value in many fields such as adsorption,catalysis,energy storage and so on.As a supplement to traditional microporous materials and porous polymers,PIPs can further expand the application range of porous polymers because its charged groups can be both the active site and catalytic center for binding with gas,and can also improve the ionic conductivity and water solubility of polymers.In recent years,photothermal conversion materials with wide solar absorption and high conversion efficiency have been widely used in solar steam generation.In practical application,the salt resistance of photothermal conversion materials will seriously affect the production efficiency of clean water,therefore,the development of high-efficiency photothermal conversion materials with salt resistance at the same time has special significance.Aiming at the above problems,this paper takes the research and development of salt-resistant photothermal conversion materials as the starting point,we proposed to prepare PIPs with different ionic groups using aromatic monomers containing as block units through Sonogashira-Hagihara cross-coupling reaction,which were used to prepare saltresistant photothermal conversion materials,and their solar interface evaporation properties were studied systematically.The results are as follows:In the second chapter,three kinds of PIPs-based bulk materials were prepared by Sonogashira-Hagihara cross-coupling reaction using 1,3,5-triethynylbenzene,1,3-Bis(4-iodo-2,6-diisopropylphenyl)-1H-imidazol-3-ium chloride,1,3-bis-(4-iodophenyl)-3Himidazol-1-ium bromide,and 1,3-bis(4-bromophenyl)-1H-imidazol-3-ium bromide as blocks.The surface of PIPs materials was sprayed with polypyrrole(PPy)as absorbent,which could be used as solar steam generation device.The PPy-modified PIPs have a good performance on solar steam generation due to their low thermal conductivity,good surface wettability and good optical absorption properties,whose photothermal conversion efficiency is higher than 80%,and the photothermal conversion efficiency of PIP-2 is the highest,followed by PIP-1 and PIP-3.In the same time,all three polymers have excellent salt resistance,and PIP-2 evaporation efficiency is up to 89% in high salinity water(30wt%)under one sun irradiation.In the third chapter,two kinds of nanowire PIPs-based bulk materials were prepared by Sonogashira-Hagihara cross-coupling reaction using alkynylbenzene,phenylamine and iodized bipyridine salt as blocks,and the polymer surface was sprayed with ink absorber as solar steam generation device.Studies have shown that the as-prepared PIPs-based optical absorbers has excellent photothermal conversion performance and salt resistance due to their high light absorptivity,low thermal conductivity and good surface wettability,namely 81% evaporation efficiency can be obtained under one sun irradiation,and in the salt water evaporation after 6 h,the surface was not observed salt accumulation.In the fourth chapter,the Sonogashira-Hagihara cross-coupling reaction was used to prepare two novel hollow microspheres PIPs bulk materials by reacting 1,3,5-triethynylbenzene with two kinds halogenated ionic monomers.The acetylene black(AB)was coated on the PIPs to prepare the solar steam generation device,and the AB-coated PIPs with a high light absorption,combine with their low thermal conductivity and good surface wettability.Both of PIPs have excellent photothermal conversion efficiency,and the evaporation efficiency is higher than 80% under one sun irradiation,due to the inherent ionic properties of PIPs,their overall superhydrophilicity and the hydrophobicity of the AB coating.In the fifth chapter,4D hollow fiber cotton(4D-HFC)with good thermal insulation was selected as the substrate,and the intrinsic salt-resistant PIPs(PIP-5,PIP-7)and reduced graphene oxide(r GO)were mixed to load the surface of the 4D-HFC for solar steam generation.The as-prepared PIPs matrix composites have excellent photothermal conversion ability and good salt-resistance.Even in high concentration of salt water,they can still maintain good evaporation effect,and no salt accumulation is observed on the surface after 6 h continuous evaporation behavior under one sun irradiation. |
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