Fabrication And Super-hydrophobic Property Of Porous Micro/Nanofibers By Freeze-Electrospinning

Super-hydrophobic surface has a wide range of applications in the daily life,industrial production,environmental protection and oil water separation,along with its anti-adhesion,anti-corrosion,self-cleaning and other functions.It has found that the high surface roughness and low surface energy are the two essential conditions to achieve the super hydrophobicity.And now,it is one of the important research directions for the preparation of superhydrophobic surfaces to obtain micro/nanofiber membrane by electrospinning technology to increase surface roughness.Therefore,it becomes an urgent problem to be solved about how to increase the roughness of the fiber while increasing its specific surface area.In this paper,the microstructure of single fiber was successfully prepared by freeze-electrospinning.The formation mechanism of PS and SiO₂micro/nanofibers with graded porous structure was successfully prepared and the formation mechanism of porous structure on single fiber was analyzed.In order to solve the problem of the SiO₂ fiber strength decrease,the anti-solvent method was proposed.The main results achieved are as follows:(1)Porous PS fibers can be prepared by electrospinning at low temperature.Of which PS is 35 wt%,1mL camphene,70%RH humidity,porous fibers with hierarchical pore structure were prepared,which had small and big pores on the fibers surface,that these pore size distribution concentrated in the range of 200-300 nm,the specific surface area was 2 times that of ordinary PS fibers,and had super hydrophobic properties.(2)The porous SiO₂ fibers were successfully prepared by the method of low temperature electrospinning.It was found that the internal and external surface porous structure are caused by camphene,while the humidity has a great influence on fiber diameter and pore structure.Moreover,the specific surface area of the porous fiber was about 5 times that of the common fiber.Oil absorption ratio of the modified porous SiO₂ fiber membrane reached 35 times while the ordinary fiber was only 14 times,and this value was significantly greater than the ordinary ones after the adsorption to reach 5 times,thus the porous fiber membrane has more advantage of the surface adsorption to remove oil spill.(3)Using of steam to promote the precipitation of the polymer PS and the solvent effect of receivers,through the desolvation method leads to the formation of a jet rapid solidification and porous structure,SiO₂ fiber with dense internal and porous surface was successfully achieved.The diameter distribution of porous SiO₂ fibers prepared by anti-solvent method was mainly concentrated in the 700-1100 nm range,the lapping joint aperture was mainly distributed in the 300-900 nm range,and the pore size of fiber surface was concentrated in the 100-200 nm interval when the receiving distance was 10 cm.