A novel electromagnetism‐assisted imprinting technology to replicate microstructures onto a large‐area curved surface using a flexible magnetic mold

Abstract

Replication of microstructures from a mold onto a curved surface is difficult. The conformal contact between the mold and the substrate has to be ensured. The present study proposes an innovative mechanism, which employs an electromagnetic disk to provide magnetic force and a PDMS flexible mold with a layer compounded magnetic powder. This mechanism provides not only the gradual contact from center to edge to avoid air entrapment but also conformal contact between the mold and the substrate during the imprinting operation. A system based on this electromagnetic soft imprinting technology has been implemented, and imprinting to replicate microstructures from the mold onto a curved surface has been carried out. The results reveal that the PDMS magnetic mold and the electromagnetic disk‐controlled magnetic force can successfully perform the imprinting and accurately replicate the microstructures onto the large‐area, curved surface glass. The PDMS flexible magnetic mold incorporated with the magnetic disk can be employed to achieve the conformal contact between the mold and the substrate. In addition, due to the low surface free energy of the PDMS, the de‐molding without sticking can be easily accomplished. Copyright © 2008 John Wiley & Sons, Ltd.

Induction heating ferromagnetic particles embedded PDMS mold for microstructure embossing

“…Gao et al [10,11] proposed an air-cushioned imprinting method. Weng et al [12][13][14][15] developed an electromagnetically controlled magnetic soft mold imprinting technique. Although the research can use PDMS soft molds for hot embossing and replicating microstructures, there is no comprehensive study to prove that it is entirely feasible to use PDMS soft molds as imprinting technology under a hot embossing machine.…”

Micropatterning of Nonplanar Surfaces on 3D Devices Using Conformal Template Vacuum Bagging

“…In these approaches, the pattern is molded onto a flexible poly(dimethyl)siloxane (PDMS) stamp, which can conform to the surface of an object; then the transfer is typically accomplished by solvent‐assisted embossing, hot embossing, or imprint lithography . These approaches benefit from the high resolution of 2D microfabrication, but can only be used on small radius of curvature substrates or objects with individual bends . Therefore, more recently flexible phase shift masks evolved as a powerful tool for patterning of photopolymers on complex surfaces .…”

Microstructure formation via roll-to-roll UV embossing using a flexible mould made from a laminated polymer–copper film

“…Continuous roller-pressing processes have been currently applied in industrial fields such as flexography printing and gravure printing [33]. A flexible PDMS magnetic mould and an electromagnetic diskcontrolled magnetic force can replicate the microstructures onto large-area, curved surface glass, which finds applications in micro-sensory and optical facilities [34]. An approach for soft nanoimprint lithography on nonstandard sample sizes has been proposed, which uses PDMS as a flexible mould material [35].…”