Design of Janus Particles by Bipolar Electrochemistry at the Water–Organic Interface

Abstract

Janus particles have a wide range of applications in diverse fields due to the possibility to tailor and combine different functionalities on a single particle. However, most of the current techniques for the synthesis of Janus particles are still suffering from limited control of the generated asymmetry. Therefore, achieving the synthesis of bifunctionalized Janus particles with a completely tunable modification ratio between two components is still extremely challenging. In this context, bipolar electrochemistry (BE) offers unique advantages to achieve controlled asymmetry in terms of the precise spatial distribution of electrochemical reactions at the two polarized extremities of a bipolar electrode. We propose herein an approach to synthesize Janus particles at the water/organic (w/o) interface by bipolar electrochemistry. Janus particles with varying degrees of amphiphilicity are first prepared by bipolar electrochemistry and are then positioned at the w/o interface. Subsequently, highly controlled bifunctionalization is achieved by carrying out different electrochemical reactions on their two sides. The ability to selectively modify the hydrophilic and hydrophobic regions allows for the generation of Janus particles with tailored properties at each face. This approach can be adapted for the synthesis of asymmetric particles with different dimensions, having various compositions and functionalities, thus opening up potential applications, ranging from catalysis and sensing to the delivery of active compounds.