Defined Transfer of Colloidal Particles by Electrochemical Microcontact Printing

Abstract

Abstract Soft lithography, in particular microcontact printing (µCP), represents a well‐established and widespread class of lithographic patterning techniques. It is based on a directed deposition of molecules or colloidal particles by a transfer process with a micro‐structured stamp. A critical aspect of µCP is the adhesion cascade that enables the directed transfer of the objects. Here, the interfacial properties of a µCP‐stamp are tuned electrochemically to modify the adhesion cascade. During the printing process, the µCP‐stamp is submerged in an electrolyte solution and acted as a working electrode whose surface properties depended on the externally applied potential, thus enabling in situ rapid switching of its adhesion properties. As a proof of principle, defined particle patterns are selectively removed from a monolayer of colloidal particles. The adhesion at the particle/solid interface and the transfer mechanisms are determined by using the colloidal probe technique based on atomic force microscopy (AFM). In this case, a single particle is brought into contact with an electrode with the same surface chemistry as the µCP‐stamp. Hence, it became possible to determine the electrochemical potential ranges suitable to establish an adhesion cascade.

Keywords

• colloidal adhesion
• direct force measurements
• electrochemistry
• microcontact printing
• soft lithography