Preparation of nickel doped multi-functional micro-patternable polydimethylsiloxane nanocomposite polymer with characterization of its magnetic, electrical and mechanical properties for soft MEMS/Lab on a chip applications

We present the preparation and characterization of a novel polydimethylsiloxane (PDMS) multifunctional nanocomposite with electric and magnetic properties. The composite is fabricated by ultrasonic agitation of nickel nanoparticles in the PDMS matrix. The prepared nanocomposite is micromolded using conventional soft lithography techniques down to a feature size of 20μm. Microstructures including coils and cantilevers are molded against a poly(methyl methacrylate) mold fabricated via Deep UV LIGA. Nickel polydimethylsiloxane nanocomposites containing up to 45.5 % Nickel nanoparticles by weight in a polydimethylsiloxane matrix demonstrate the largest saturation magnetization of 21.0 emu/g as measured by SQUID magnetometry. It is also observed that the Young Modulus is a linear function of filler loading up to 50 wt% and indicates a material with superior mechanical properties as compared to undoped polydimethylsiloxane. The insulator–conductor transition for the nickel-polydimethylsiloxane composite occurs at 40 wt.%.