The Assembly And Application Of Cellulose Nanocrystal At Liquid Liquid Interfaces

It is one of the frontiers in the field of research to prepare multi-level ordered functional materials by self-assembly of nanoparticles at the liquid-liquid interface.In this study,firstly,cellulose nanocrystals(CNC)were dispersed in the aqueous phase and interacted with the amino-terminated polystyrene(PS-NH2)ligand in the oil phase.Then,it studied the rheological behavior of self-assembled membranes of CNC and PS-NH2 at the water-oil interface by adjusting the pH of the aqueous phase,the molecular weight and the concentration of PS-NH2.What's more,graphene oxide(GO)and CNC were dispersed in water to study the self-assembly behavior of GO/CNC and PS-NH2 at the interface,and further preparation of porous materials.The main progress and results are as follows:1.The rheological properties of CNC and PS-NH2 self-assembled films was studied.Results show that the elastic modulus of self-assembled films increased with the increase of dilatational frequency,concentration and molecular weight of PS-NH2.As the pH of the aqueous phase and the dilatational amplitude increase,the elastic modulus of the self-assembled film decreases.As the concentration of CNC in the aqueous phase increases,the elastic modulus of the self-assembled film increases first and then decreases.At the same time,the loss modulus increases first and then decreases as the dilatational frequency increases.The change of rheological properties of self-assembled membranes with pH,the concentration of CNC,concentration and molecular weight of PS-NH2 is the result of different assembly and disassembly rates of CNC at the liquid-liquid interface.It proves a transformation from "liquid-like" to "solid-like" of the assembled membranes.2.The self-assembly behavior of GO/CNC and PS-NH2 at the water-oil interface was studied.Results show that the pH of the aqueous phase has a significant effect on the interfacial tension of water-oil.When the pH of the aqueous phase is reduced from 7 to 3,the interfacial tension decline from 21 mN/m to 16 mN/m,and when the pH is more than 5,the interfacial tension does not change.However,the interfacial tension did not change significantly with the GO concentration,concentration,and molecular weight of PS-NH2.3.Prepare porous materials by the self-assembly of GO/CNC and PS-NH2 at the water-oil interface.Results show that the greater the interfacial tension at water-oil interface reduction,the more stable the emulsion formed,and the pore size of the prepared porous material is small and uniform.When the pH of the aqueous phase is 3 and the molecular weight of the oil phase PS-NH2 is 0.8k,the pore diameter of the porous material is the smallest.thereby realizing the preparation of the porous material with different pore diameters by regulating the interfacial tension.Although the change of GO content has no effect on the interfacial tension,it has a great influence on the morphology of porous materials.