The preparation of amphiphilic colloidal particles with hydrophobic core and hydrophilic shell

Amphiphilic colloidal particles were prepared with hydrophobic polystyrene cores encapsulated by hydrophilic polyacrylamide shells. The polystyrene colloidal particles were prepared by using a concentrated emulsion as a precursor. The polyacrylamide shell is prepared via redox initiation. A notable feature of the particles is that no copolymer jointing portions exist. The hydrophobic cores were just encapsulated by hydrophilic shells. The porous shell ensured the hydrophobic cores accessible to the outside media. As a result, such particles could be dispersed in both water and diesel oil. That is to say, they were compatible with both polar and nonpolar solvents. SEM photographs confirmed the shell structure. The amphiphilicity of the particles was characterized by their water and diesel oil absorbabilities. It was found that polymerization recipes and reaction conditions, the amount of redox initiator, diluent, hydrophilic monomer, crosslinker and the temperature of polymerization, could adjust the structure and thickness of the hydrophilic shells. Such amphiphilic colloidal particles can be used widely in drug delivery and catalytic processes.