PDMS Stamping Device for Double-Sided Janus Particles

¹The City College of New York, Department of Chemical Engineering

Janus particles have at least two different materials on their surface and are studied for potential applications in targeted drug delivery, optical sensing, and more. Janus particles can also be coated with materials on both sides, i.e., double-sided Janus particles, which can have unique properties such as active magnetic fluids and magnetic assembly. The process of placing two coatings requires a complicated stamping approach that is difficult to control, leading to reduced reproducibility of the stamping process and low quality of the double-sided Janus particles.

Here we report on the design of a device that has the capacity to simultaneously stamp up to seven slides with Janus particles onto PDMS-coated microscope slides. This approach makes the stamping of the particles easier, faster, and more reproducible. It also scales up the process currently used in the laboratory. With the help of the PDMS stamping device, we are able to process more than one slide at a time and control the force applied during the stamping process. The device’s performance has been tested using sensors on different spots where the slides are placed, collecting data to determine the best time and weight for the stamping, and using the device to make double-sided particles, which have been characterized to check the quality of the resulting particles. Double-sided particles have been coated using physical vapor deposition (PVD) and the coatings have been checked using a scanning electron microscope (SEM). Moreover, the behavior of the double-sided Janus particles that have been made with this device have been studied, which have magnetic properties and can self-assemble.