In Situ Fabrication and Actuation of Polymer Magnetic Microstructures

• Published in: Journal of microelectromechanical systems Vol. 20; no. 4; pp. 785 - 787
• Main Authors: Su Eun Chung, Jiyun Kim, Sung-Eun Choi, Kim, Lily Nari, Sunghoon Kwon
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.08.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuation; Actuators; Applied fluid mechanics; Channels; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fabrication; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Magnetic fields; magnetic materials; Magnetic resonance imaging; Magnetic separation; Materials science; Mechanical instruments, equipment and techniques; Methods of nanofabrication; Microactuators; microassembly; Micromechanical devices and systems; Microstructure; photolithography; Physics; Polymers; Rails; Resins; Self-assembly; Silicone resins; Transducers; Actuators; Precision engineering; Polyethylene glycols; Cantilever beam; Electromagnetic devices; Fabrication; Rail; Polyacrylates; Photopolymerization; Magnetic devices; micro-assembly; Photolithography; Floating body; Microelectromechanical device; Nanomaterial synthesis; Sacrificial layer; Production process; Magnetic properties; Dimethylsiloxane polymer; Patterning; Microactuators; Light sensitive polymer; magnetic materials; Microfluidics; Fluidics
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2011.2159093

We demonstrate a single-exposure in situ magnetic actuator fabrication technique using magnetic nanoparticles (MNs) containing UV curable polymer in a Polydimethylsiloxane (PDMS) channel. Microstructures with a 3-D anchored cantilever as well as free-floating components are fabricated in a single step at a single site without the use of a sacrificial layer. By controlling the location of high oxygen concentration area through PDMS substrate patterning, we can create partially bound and free-floating movement-restricted structures. This allows us to create complex magnetic actuators, such as a 3-D anchored cantilever, motor type, and rail-guided magnetic actuators. The actuating performance of UV photopatterned magnetic microstructures depends on the MN concentration in photopolymer resin and magnetic field intensity. The measured translational velocity of magnetic microactuators with a 1 : 10 MN concentration is 140 μm/s under 1400 G of magnetic field in poly(ethylene glycol) diacrylate resin. Also, we demonstrate selective magnetic actuation of heterogeneous structures composed of magnetic and nonmagnetic parts self-assembled in railed microfluidic channels. Only magnetic parts from the assembly selectively actuated due to the magnetic field without response to the flow. Therefore, we have developed a versatile magnetic microstructure fabrication method that is very simple and fast, enabling rapid in situ fabrication and actuation.