In-situ Self-assembly Behavior Of DBS In Porous Media And Its Application

Low molecular mass organic gelators(LMOG)can self-assembly nanofibers in porous materials by non-covalent interactions.This is a "bottom-up" method making nanofibers that can effectively regulate the structure of the porous nanofibers.In this paper,based on our previous work,firstly,we put LMOG into the solution blowing nanofibers to explore the regulation of self-assemble nanofibers,and prepared gel nanofiber-spinning nanofiber membrane to microfiltration research.Secondly,LMOG was introduced into the PVDF microfiltration membrane to construct self-assembled nanofibers-Nafion composite proton transport channel,and prepared the proton exchange membrane study the membrane performance.The details are as follows:The effects of solvent polarity,hydrogen bonding force and DBS concentration on the formation of DBS in nanofibrous membranes were investigated;the results showed that the self-assembled nanofibers of DBS were affected by solvent polarity,solvent hydrogen bonding and the concentrations of DBS.In a certain concentration range,DBS self-assembled fewer nanofibers in the strong polar of solvent.On the other hand,a large amount of DBS nanofibers assembled in the weak solvent polarity.The diameter of DBS nanofiber decreases with the increasing of solvent polarity.DBS also self-assembled fewer nanofibers in the strong solvent hydrogen bonding and more homogenous DBS nanofibers were filled in PAN nanofibers in the weak solvent hydrogen bonding.The diameters of DBS nanofibers increased with the increases solvent hydrogen bonding.We found the morphology of DBS assembled nanofibers changed to membrane with the increase of DBS concentration,and the diameters of DBS nanofibers hardly affected with small changes in concentration of DBS nanofibers in the same solvent.With the problem of difficult to control the nanofiber structure,we prepared PAN/DBS hierarchical nanofibrous membranes by in-situ growth of DBS in solution blowing PAN nanofiber membranes.The morphology structure characterization indicated that DBS was successfully assembly into PAN nanofibers,and forming the morphology of DBS nanofibers-spinning nanofibers.The DBS nanofiber fibers filling PAN nanofibers membrane enhanced the mechanical properties,pure water flux and the filtration efficiency was greatly improved.The rejection of particles larger than 1.3 ?m even up to 100%;PAN/DBS nanofiber membrane performance evaluation results show that the membrane has a good anti-pollution effect,and showed a good stability containing organic solvents such as aqueous butyl acetate solution.With the problem of poor swelling and poor alcohol retention ability of Nafion membrane,a proton exchange membrane was prepared by in situ self-assembly of DBS in PVDF membrane.The structure and properties of the membrane were studied.The results show that DBS successfully assembly nanofibers in the PVDF membrane,and Composite membrane had good proton conductivity and alcohol resistance,as well as a higher water absorption,lower swelling rate and good dimensional stability compared to PVDF/Nafion membrane.