All ETDs from UAB

Advisory Committee Chair

Derrick R Dean

Advisory Committee Members

Shane A Catledge

Vinoy Thomas

Yogesh Vohra

Nitin Chopra

Document Type

Dissertation

Date of Award

2014

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

As more technology shifts from the microscale to the nanoscale, the demand for new fabrication and characterization methods to investigate material properties on the nanoscale significantly increases. Dip-pen nanolithography is an innovative printing technique with the precision to deposit a multitude of inks with nanoscale dimensions on a variety of substrates. This bottom-up approach of high-throughput printing has enabled the study of nanomaterials spanning the gamut of disciplines from nanoelectronics to single-cell interactions to drug delivery. However, the scalability and reproducibility of the dip-pen nanolithography platform has yet to reach full potential in terms of large-scale material production. Specifically, the dip-pen nanolithography platform can address some of the challenges that hinder the development of two polymer systems, tissue engineering polymer systems and electroactive polymer systems. This work utilizes dip-pen nanolithography as a basis for creating nanocomposites for tissue engineering and `smart' materials by the functionalization and characterization of novel polymer blend scaffolds and electroactive polymer systems. Additionally, this work enhances the application areas of the dip-pen nanolithography system with specific impacts on nanotechnology and the advancement of unique polymer systems. The work begins with electrospinning polymer blends of polycaprolactone and polyglyconate for the first time. The mechanical, rheological, thermal and morphological behaviors of the electrospun blends provide guidance for the design and optimization of hybrid scaffold systems. This provided a matrix for dip-pen nanolithography patterning with hydroxyapatite inks. Nanoparticle based inks of hydroxyapatite were designed for specific use with dip-pen nanolithography. The inks were tested in terms of stability, dispersion, and accuracy of patterning to determine the optimal formulation for high throughput printing onto electrospun scaffolds. In addition to tissue engineering applications, this work also focused on developing new techniques to pattern carbon nanotubes on electroactive polymer films in the nanoregime. Carbon nanotubes inks were formulated as a nanoparticle-based ink for dip-pen nanolithography patterning. These formulations led to the first reported direct deposition of multi-walled carbon nanotubes by dip-pen nanolithography with printed features ranging from 400 nm to 4 µm. These carbon nanotube features were printed onto polymer films as ongoing work to develop electroactive polymer composites using dip-pen nanolithography.

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