Preparation, Characterization, and Properties of Hollow Janus Particles with Tailored Shapes.pdf

Preparation, Characterization, and Properties of Hollow Janus Particles with Tailored Shapes Hongbin Hou,?,? Demei Yu,*,?,? Qiong Tian,§ and Guohe Hu§ ?Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, Ministry of Education, School of Science, ?State Key Laboratory of Electrical Insulation and Power Equipment, and §School of Science, Xi’an Jiaotong University, Xi’an, 710049, People’s Republic of China ABSTRACT: As compared to the traditional solid Janus particles, the hollow Janus particles have inspired growing interests due to their diverse potential applications. Herein, the novel hollow Janus particles with elephant trunk-like and acorn-like shapes were prepared by seed emulsion polymer- ization. In contrast to traditional template methods, the hollow structure was obtained during the preparation by one-step swelling method. The shapes and internal structures of hollow Janus particles were confirmed, and the compositions were identified too. Some critical influences on the morphology control were investigated, that is, the surface modification, the amount of surfactant, and cross-linking agent concentrations. It was inferred that the balance of hydrophilicity and hydrophobicity and the effective phase separation were important for preparing the hollow Janus particles with tailored shapes. Finally, amphiphilic properties of hollow Janus particles were demonstrated by emulsifying oil?water mixture. 1. INTRODUCTION Over the past few decades, Janus particles as a structural noncentrosymmetry functional material have been extensively studied due to their unique properties. However, most of the currently reported Janus particles were solid, and only a few pieces of literature reported on hollow Janus particles. In fact, hollow Janus particles with tailored structures have attracted more attention due to their potential applications in various fields such as controlled-release capsules of various substances (drugs, cosmetics, dyes, and in