Micromanipulator controlled fabrication of micro-and nanoscale polymer fibers and application as sacrificial structures in the production of microchannels

Suspended micro-and nanoscale polymer fibers were created using a new and novel technique which is performed at room temperature. This method involves drawing solvated PMMA into liquid filaments, which thin, via surface tension, as the solvent evaporates, subsequently yielding a solid fiber. The PMMA solution was drawn by two separate techniques: 1) using a stylus to extrude a solution filament between two pre-deposited pools, and 2) using a pressurized capillary loaded with solution to directly deposit filaments of solution on the substrate in a “connect-the-dots” style. Also, because both the stylus and pressurized capillary were controlled with an ultra-high precision instrument, the fibers can be precisely positioned in three dimensions. The diameters of these fibers were controlled, within the range of 450 nm to 100 µm, by varying the molecular weight of the polymer or the concentration of the PMMA solution. It was discovered that increasing either or both of these variables led to an increase in fiber diameter. Also, the effect of stylus material on fiber diameter variance was examined, with a Parylene®-coated stylus yielding the lowest overall variance. These fibers were coated with glass and Parylene® and dissolved to produce hollow microchannels suitable for electroosmotic flow. Electroosmotic channels with diameters ranging from 4 µm to 100 µm were successfully fabricated and tested.