Preparation And Application Of Polystyrene Honeycomb Porous Membrane

Honeycomb porous membrane has a very broad application prospect in optoelectronic devices,biomaterials,sensors,template materials,separation and filtration,etc.because of its high specific surface area,large roughness and uniform pore structure.For the preparation of the honeycomb porous membrane,there are mainly an emulsion droplet template method,a colloidal crystal template method,a surfactant self-assembly method,a microphase separation template method,and the like.However,these methods all have to remove the template,and there are problems such as destruction of the porous structure and difficulty in removing the template during the process of removing the template.Therefore,in this paper,a polystyrene(PS)honeycomb porous membrane is prepared by the breath figure(BF)method and the vapor-induced phase separation(VIPS)method which do not require removal of a template.Firstly,in this thesis,PS honeycomb porous membrane was prepared by the breath figure(BF)method.The effects of solvent type,ambient humidity and solution concentration on the morphology of PS porous membrane were studied.The results showed that chloroform was a good solvent for the preparation of PS porous membranes.When the relative humidity was in the range of 68-85,the pore size of the porous membrane increased with the increase of humidity,and the spherical degree of the pores did not change much;when the concentration was 13 mg In the range of /ml-45 mg/ml,as the concentration increases,the pore size of the porous membrane decreases and the sphericity of the pores decreases.Subsequently,in this thesis,a modified honeycomb method was used to prepare a PS honeycomb porous membrane,and the effects of the non-solvent phase,non-solvent ratio,ambient humidity,and solution concentration on the morphology of the PS porous membrane were investigated.The results showed that acetone,methanol and ethanol could be used as good non-solvent phases.When methanol was used as non-solvent phase,the ratio of chloroform to methanol was 90:10 and 95:5 to obtain a relatively regular porous membrane;in the range of 55-85,as the humidity increases,the degree of spherical bore little change,increasing size of the porous membrane,but slower than the rate of increase BF method;when the concentration of 13 mg/ml-45 mg/ml In the range of ml,as the concentration increases,the pore size of the porous membrane decreases,and the sphericity of the pores decreases,but the rate of decrease is slower than that of the BF method.Further,in this paper,the effect of the porous structure on the PS film on the hydrophilicity was investigated,and the PS film was subjected to ultraviolet crosslinking.The results show that the hydrophobicity of the film increases with the appearance of porous structure on the PS film,and the hydrophobicity of the porous film increases with the increase of the pore size.After UV crosslinking,the static contact angle of the PS film is reduced to 15.4 °,greatly enhance hydrophilicity;and,PS film after UV-crosslinked at a temperature of 250 °C and soaking at the PS common solvents(chloroform,tetrahydrofuran,toluene,acetone)still able to maintain a more complete porous structure.Finally,the PDMS elastic seal was prepared in this paper.The PS porous film with regular spherical structure was prepared at room temperature(25 °C)to 120 °C with cross-linked PS porous membrane as template.The results show that the higher the curing temperature,the smaller the hydrophobicity of the PDMS seal and the slightly increased hardness.At the same time,the hydrophobicity of the PDMS seal increases with the increase of the diameter of the surface sphere.