Design and Characterization of "Stimuli Responsive" Supramolecular Nanocomposite Systems

Supramolecular nanocomposite materials have emerged as an interdisciplinary research area that exploits synergistic relationships at the nanoscale to enhance the electrochemical properties of next-generation responsive systems. Therefore, mechanistic understanding tailored to the nuances are greatly needed. This seminar will present two case studies. The first focuses on Chemical Mechanical Planarization (CMP) which is a critical polishing process step in advanced integrated circuit manufacturing. This work utilizes photo-switching mechanisms to tune the slurry nanoparticle surface to enhance its electrophilicity and ultimately increase removal rate upon irradiation. More specifically, there are two modes of photo-switching to modulate oxide removal rates: a photo-induced adsorption/desorption mechanism to alter oxygen vacancy availability and a light-induced ligand-metal-charge transfer (LMCT) in which the particle is reduced, and the functional additive is desorbed, allowing for greater oxygen vacancies and less steric hindrance. The second case study focuses on biomimetic nanocomposite matrices which have emerged as polymeric scaffolds that exploit synergistic relationships to enhance physiochemical properties from natural biopolymers which take advantage of their well-defined, three-dimensional network and intrinsic properties. This work will discuss the strategic design of hydrogels, emphasizing the selection of the biopolymer network and the critical role of incorporating additives, have on the resultant properties of the nanocomposite such as swellibility. Furthermore, the addition of AgTiO 2 nanoparticles provides a contact-based antimicrobial activity and enhanced closure rates of simulated wounds in adult human dermal fibroblasts (HDFa). Secondary functionalization of the backbone via metal-coordination assisted photopolymerization of conductive polymers add surface sensing capabilities. Upon the addition of simulated wound exudate, the swelling capacity of the biopolymer network enabled the detection (i.e., surface impedance) of changes in the local ionic strength. The resultant electrochemical change can be tracked and sent to an external signal source (i.e., an LED or Bluetooth signal), indicating that the surface is saturated with wound exudate.