Research On Hydrophobic Cellulose Nanocrystal Stabilized Ionic Liquid/Water System Pickering Emulsion

Pickering emulsion plays an important role in food,pharmaceutical,controlled release and other fields due to its low toxicity,high stability and multiple stimulus response characteristics.Traditional water/oil system（such as water/toluene system）is volatile and harmful to environment and has biological toxicity.Ionic liquid（IL）is an environmentally friendly and structurally adjustable liquid material with low melting point and high thermal stability,which has important applications in catalysis,biological adsorption,enzymatic reaction and other fields.Therefore,it is of wide application value to explore a green,simple and efficient method to construct Pickering emulsion system with IL.Among Pickering particles,cellulose nanocrystals（CNC）come from a wide range of sources and have excellent properties such as renewable,non-toxic,high strength and high transverse to longitudinal ratio.This paper bases on the water-IL system,CNC as the surfactant of nanoparticles,through the electrostatic adsorption of CNC and IL,the biofriendly IL Pickering emulsion was quickly and efficiently constructed,and its functional application was further explored.The main research contents of this paper are as follows:1.Based on the water and IL system,this paper selects sulfonated cellulose nanocrystals to stabilize the water and IL interface,and systematically studies the adsorption behavior of CNC in the water-IL system by tracking the interface dynamics data.By grafting fluorescent groups on the surface of CNC,the adsorption behavior of CNC at the interface between water and IL was visually observed.IL/w Pickering emulsion was prepared with CNC as surfactant,and the factors affecting the size and stability of Pickering emulsion were studied.2.Hydrophobic CNC-C₈ and CNC-C₁₈ were obtained by alkyl chaining of CNC.The microstructure,particle size distribution and surface charge were characterized,and the influence of the length of the grafted alkyl chain on the wettability and dispersion of hydrophobic CNC was investigated.Hydrophobic CNC was used to stabilize the interface between water and IL,and IL/w Pickering emulsion and w/IL Pickering emulsion were prepared by adjusting the volume ratio of water and IL.By changing the type of IL,the Pickering emulsion of various water-IL systems was stabilized by hydrophobic CNC,which verified the universality of hydrophobic CNC to stabilize water-IL systems.3.Based on the adsorption of hydrophobic CNC at the interface between water and IL,IL/w high internal phase Pickering emulsion（HIPPE）was prepared by a two-step method.HIPPE was used as 3D printing ink for 3D printing,and customized pattern devices were constructed.The printed pattern morphology was complete and remained stable under gravity conditions.IL microspheres were prepared and characterized with hydrophobic CNC stabilized Pickering emulsion as template using IL system with water and melting point higher than room temperature.