단분산성 양친성 야누스 마이크로입자의 합성 및 계면배향에 관한 연구

Abstract

This study introduces a straightforward and robust polymerization method for synthesis of uniform polymer microparticles having controlled surface chemistry as well as tailored particle shapes. Uniform polystyrene (PS) microparticles are produced by dispersion polymerization, in which amphiphilic poly (ethylene oxide)-b-poly (?-caprolactone) (PEO-b-PCL) copolymers anchor on the growing polymer particles and stabilize them by the steric repulsion effect. We have observed that when PEO-b-PCL copolymers are incorporated at a proper concentration range, the total number of particles remains unchanged after formation of primary particles, which is essential for maintaining the size uniformity. Otherwise, non-uniform PS microparticles are produced due mainly to the coagulation or secondary formation of particles. To show diversity of our particle synthesis technology, shape-controlled microparticles, such as dimples and Janus particles, are also produced by using the temperature-mediated swelling and phase separation. Finally, we show that PEO-b-PCL copolymers play a key role in regulating the surface wettability of the seed particles, thereby facilitating formation of anisotropic microparticles.|In this study, we introduce a facile and promise approach to synthesize monodisperse Janus microparticles with controllable phase compartmentalization and surface amphiphilicity. The technique we employed to synthesize the Janus microparticles is the seeded swelling and polymerization. For this, polystyrene (PS) seed particles are uniformly swollen with alkyl acrylate monomers having the different length of alkyl chains from C6 to C16. Upon polymerization, a bicompartmentalized Janus morphology is generated depending on the interfacial free energy. When tetradecyl acrylate (TA) is used, complete compartmentalization into two distinct phases, PS and poly (tetradecyl acrylate) (PTA), can be achieved. More meaningfully, we are able to precisely control relative compartment dimension ratio from 0.25 to 0.5. Finally, we have demonstrate that patching silica nanoparticles onto one of the compartment surfaces produces amphiphilic Janus microparticles that are able to assemble at the oil-water interface with a designated level of adhesion, thus leading to development of a highly stable Pickering emulsion system.; In this study, we introduce a facile and promise approach to synthesize monodisperse Janus microparticles with controllable phase compartmentalization and surface amphiphilicity. The technique we employed to synthesize the Janus microparticles is the seeded swelling and polymerization. For this, polystyrene (PS) seed particles are uniformly swollen with alkyl acrylate monomers having the different length of alkyl chains from C6 to C16. Upon polymerization, a bicompartmentalized Janus morphology is generated depending on the interfacial free energy. When tetradecyl acrylate (TA) is used, complete compartmentalization into two distinct phases, PS and poly (tetradecyl acrylate) (PTA), can be achieved. More meaningfully, we are able to precisely control relative compartment dimension ratio from 0.25 to 0.5. Finally, we have demonstrate that patching silica nanoparticles onto one of the compartment surfaces produces amphiphilic Janus microparticles that are able to assemble at the oil-water interface with a designated level of adhesion, thus leading to development of a highly stable Pickering emulsion system.