UC San Diego
Design and Fabrication of Nano-Bio Materials for Sensor and Device Applications
- Author(s): Choi, Duyoung
- et al.
In this thesis, various aspects of nano-bio materials have been discussed including novel design, fabrication and applications of nanopatterned graphene for sensor and device by using self-assembly techniques. First, we demonstrate a successful fabrication of nano-patterned graphene (NPG) using a Poly(styrene-b-4-vinylpyridine) (PS -b-P4VP) polymer, which was never used previously for the graphene patterning. This work also demonstrates that block copolymer (BCP) lithography is a pathway for low- cost, high throughput large scale production of NPG with critical dimensions down to nanometer regime. Second, Thin anodized aluminum oxide nano-mask was prepared by facile self-assembly technique without using polymer buffer layer, which was utilized as direct-contact template for oxygen plasma etch to produce near periodic, small-neck-width NPG. This work also demonstrates that our direct-contact, self-assembled mask lithography is a pathway for low-cost, high throughput, large scale nanomanufacturing of graphene nano devices. Third, we demonstrate here a successful fabrication of optically highly transparent (̃98%) graphene layer having a reasonable electrical conductivity by nano-patterning and doping. AAO nanomask prepared by simple self-assembly technique was utilized to produce an essentially hexagonally NPG. The results indicate that the NPG approach can be a promising route for simultaneously tuning the optical and electrical properties of graphene to make it more light-transmissible and suitable as a flexible transparent conductor. Fourth, the fabrication of large-scale graphene-nanoribbon (GNR) network and its application for gas sensing are reported. GNR network shows significantly enhanced sensitivity to ammonia gas compared to pristine graphene. The detection sensitivity of the nanoscale GNR network is even further improved by decorating GNR network with palladium (Pd) nanoparticles, which shows a relative resistance response of 65 % to 50 ppm of ammonia in nitrogen at room temperature as well as good reversibility in air. Fifth, we have successfully prepared PLGA-coated nanocapsules that allow a switchable drug release on remote RF magnetic field actuation, and are capable of tumor penetration with their powerful magnetic vector. The biodegradable PLGA-polymer-coating on the nanocapsule surface intentionally delays the diffusional leakage of the therapeutic drugs through the nanopores in the wall of the hollow capsules that contain the magnetic nanoparticles and the desired therapeutic drugs