A magnetic poly(dimethylesiloxane) composite membrane incorporated with uniformly dispersed, coated iron oxide nanoparticles

• Published in: Journal of micromechanics and microengineering Vol. 20; no. 1; pp. 015032 - 015032 (7)
• Main Authors: Pirmoradi, Fatemeh(Nazly), Cheng, Luna, Chiao, Mu
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2010; Institute of Physics
• Subjects: Adsorption and desorption kinetics; evaporation and condensation; Agglomeration; Application fields; Applied sciences; Coated particles; Coatings; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deflection; Dispersions; Exact sciences and technology; Fatty acids; Iron oxides; Magnetic fields; Materials science; Mechanical engineering. Machine design; Membranes; Microelectromechanical systems; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Optical properties; Particle size; Particulate composites; Physics; Polymer industry, paints, wood; Precision engineering, watch making; Saturation (magnetic); Silicone resins; Solid-fluid interfaces; Stress strain curves; Stress-strain relationships; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Technology of polymers; Tensile tests; Dimethylsiloxane polymer; Biotechnology; Particle size; Tensile tests; Mechanical properties; Hydrophobic compound; Micropumps; Artificial membrane; System on a chip; Rough surfaces; Aggregation; Nanoparticles; Magnetic particles; Composite materials; Composite coating; Optical properties; Magnetic materials; Microelectromechanical device; Nanotechnology; Microfluidics
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/20/1/015032

We report a new magnetic polymer membrane for MEMS application. The polymeric magnetic composite has coated iron oxide nanoparticles incorporated in a polydimethylsiloxane (PDMS) matrix. Existing magnetic polymeric materials have particle agglomeration problems, which result in rough surfaces and uneven mechanical and optical properties. We show that the use of iron oxide nanoparticles (10 nm in diameter) with fatty acid and hydrophobic coatings inhibits aggregation of particles in the PDMS polymer matrix. Agglomerated particle sizes in thin-film PDMS composites incorporated with uncoated and coated particles are 51 +/- 24 *mm and 1.6 +/- 0.25 *mm, respectively. The PDMS composites exhibit saturation magnetization of 22.8 to 23.94 emu g-1. Stress-strain curves of the composites are characterized by tensile tests. Free-standing magnetic PDMS membranes are fabricated in different sizes from 4 mm to 7 mm in diameter and with the thickness of 35.5 +/- 1.5 *mm. The membrane of 7 mm diameter achieves deflection of 625 *mm in a 0.417 T magnetic field. The magnetic PDMS membranes may be used in micro-pumps and lab-on-a-chip applications.