Modification Of Nanofibers And Construction Of Aerogel Based Polystyrene

As one of the simple and versatile methods for constructing nanofibers,electrospinning technology is widely used in environmental protection,biomedicine and many other fields.With the rapid development of technology,related application fields have put forward higher requirements for fiber modification and assembly.The hydrophilicity and surface charge of fibers are crucial in its modification and assembly.In this study,the low temperature plasma pretreatment solves the problems of"fiber hydrophobicity"and"surface charge"limiting its surface modification and assembly.Subsequently,this study introduced directional freezing technology into fiber assembly and prepared porous ordered aerogel for oil pollution treatment.This research mainly includes the following two parts:（1）To expand the template options of immersive electrostatic layer-by-layer self-assembly（LBL）that requires hydrophilic and protonation substrates,environment-friendly and simple plasma pretreatment that enhanced the surface charge and wettability of super-hydrophobic mats is employed to effectively assist LBL.With positively and negatively charged layers,chitosan（CS）and bovine serum albumin（BSA）were alternately deposited on the surface of polystyrene（PS）mats and O₂plasma-treated mats via electrostatic LBL.After the exposure of plasma gas at different time intervals,theζ-potential values of the mats were distinct,and the value of the mats was-30.10 m V after treating by O₂ plasma for 70 s,which was almost 5 times higher than that of the pristine PS mats.In addition,the average surface roughness（Ra）of the O₂ plasma treated mats was 116.1±12.6 nm,which was higher than that of the PS mats（87.6±14.3 nm）due to the plasma etching.The water contact angle of the PS mats was144.5±1.4°,which decreased to 0°within 0.33 s after O₂ plasma treatment,proving that the modified PS mats were super-hydrophilic.Compared with the mats without plasma treatment,the uniform deposition of CS and BSA on O2 plasma-treated mats was confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.Moreover,the mats with an enhanced surface charge and wettability after plasma treatment and LBL processing also exhibited low cell cytotoxicity and facilitated cell growth well.（2）The porous PS/poly（methylmethacrylate）（PMMA）nanofiber membranes were prepared by electrospinning.CS,epichlorohydrin（ECH）and rectorite（REC）were then introduced to prepare porous organic-inorganic composite aerogels.The optimum preparation conditions were determined by the morphology,specific surface area and elasticity of the composite aerogels.The introduction of CS and ECH increased the stability of the suspension.The porous ordered PS/PMMA-REC_0.5 aerogel was obtained after directional freeze-drying.X-ray photoelectron spectroscopy,X-ray energy dispersive spectroscopy,Fourier transform infrared spectroscopy and X-ray diffraction were used to detect the composition of the composite aerogel sample,functional group changes and crystal structure.The results showed that CS and REC were successfully introduced into the aerogels.The addition of REC increases the water contact angle of the composite aerogels and improves the hydrophobicity of the composite aerogels,which was facilitated oil adsorption.In addition,the contents of REC had an effect on the specific surface area of the composite aerogels.The PS/PMMA-REC_0.5 aerogel had the largest specific surface area of 3.0 m²/g,and its oil absorption can reach 68.34±3.01g/g.