Preparation And Study Of Cellulose-based Ordered Porous Membrane Via Breath Figure

Breath figure technology has a wide range of applications in the fields of materials science and films science.Especially,ordered porous films prepared by the breath figure method have promising applications in the superhydrophobic,biochemical and electrochemical fields.The breath figure method has many advantages,including simple operation,no pollution and low cost,which attracts the attentions by many researchers.The microscopic morphology of the porous membrane was adjusted by controlling parameters,such as solvent,concentration,humidity and chemical structure.However,the mechanism has not yet universal laws.In this paper,in order to explore the mechanism of the formation of ordered porous structure via the breath figure,using cellulose acetate as the substrate synthesized cellulose acetate with acyl chloride,phenylacetyl chloride and halogenated acyl chloride.The effects of tension,deposition rate,concentration and structure on the formation of porous membranes were investigated.The main results obtained are as follows:1.First of all,cellulose-based derivatives were synthesized by changing the ratio of reactants with different degrees of substitution and different substituents.The structures of the synthesized products were characterized by infrared spectroscopy and ~1H-NMR spectroscopy.2.The porous film structures prepared from acyl chlorides were explored and the effects of surface tension,deposition rate,structure,humidity,and hydrophobicity were discussed.The results showed that polymers with lower surface tension and faster deposition rates can be formed ordered porous films.Highly volatile solvents,higher humidity and suitable concentrations are key to the formation of ordered porous membrane structures.The pore size of the porous film decreases with increasing concentration,and the higher the humidity is,the larger the pore size is.As the degree of substitution increases and the segment of the substituent becomes longer,the pore size is smaller and the degree of order increases.The stronger the hydrophobicity is,and the smaller the pore size and the higher the order are.3.Porous membrane structure prepared from phenylacetyl chloride was studied.The results showed that the proper polymer concentration is an important condition for the formation of a honeycomb ordered porous structure.The appropriate degree of substitution and the oil-water separation coefficient are extremely important for the formation of ordered porous structures of porous membranes.Under certain conditions,the greater the degree of substitution and the oil-water separation coefficient are,the more ordered the porous film structure and the smaller the pore size are.4.The porous membrane structures prepared by halogenated acid chloride were studied.The results showed that the porous membrane structure prepared by F substitution is more orderly.As the oil-water separation coefficient increases,the pore size of the porous membrane decreases and the degree of order increases.A highly hydrophobic ordered porous film structure can be prepared by using cellulose acetate substituted with perfluorooctanoyl chloride.