The Application Of Pickering Emulsions In Controlled Release Of Drugs And Phase Change Materials

Pickering emulsions have attracted more and more researchers’attention because of their long stable time,no side effects brough by surfactants and flexiblility of solid particles’selection.They have a wide range of applications and will play an increasingly important role in biological agents,food storage,catalysis,environmental governance and other fields.At present,there are a number of reports about the preparation of drug carriers via oil-in-water emulsions for the delivery of hydrophobic drugs.However,the synthesis of safe,biocompatible and high-performance carriers for water-soluble drugs remains a challenge.In this work,polyacrylamide/carbon dot microspheres were fabricated by using carbon dots stabilizing water-in-oil Pickering emulsion as template and applied to the delivery of hydrophilic drug 5-fluorouracil（5-FU）.The encapsulation efficiencies and drug loading can be adjusted to the maximum of 82.0 and 47.9%respectively,by changing the concentration of 5-FU solution.In addition,the release behavior of 5-FU loaded microspheres performs relatively stable and sustainable,and the release mechanism can be summarized as abnormal transport.Phase change materials（PCMs）have great potential in energy utilization and storage.Among them,organic PCMs have attracted more attention due to their advantages such as non-corrosiveness and non-supercooling,but they also have obvious shortcomings,like leakage,poor thermal conductivity and low utilization efficiency of solar energy.Therefore,it is necessary to develop a kind of PCMs with no leakage,high thermal conductivity and photothermal conversion function.In this work,on the one hand,the low-cost carbon dots were modified in order to be effectively dispersed in organic PCMs to raise the thermal conductivity of PCM.On the other hand,Pickering emulsion stabilized by the modified graphite phase nitride was applied to encapsulate the PCMs.The encapsulated PCMs with surfacial positive charge could assemble with the prepared Bi₂S₃-Ag@GO which has negative charge to form O-CN/BAG-PCM composites.The composites have high thermal conductivity（46%higher than that of pure paraffin wax）,improved thermal stability and excellent photothermal conversion.