Engineering a localized pH switch at the solid-liquid interface

Duke University, Durham NC

Investigators

Abstract

The research objective of this award is to develop a new class of surface modification techniques that use programmable ferroelectric substrates to control the local hydrogen ion concentration (pH) at the solid/liquid interface. The key concept exploited in this work is that polarized ferroelectric films produce intense electric fields which can substantially alter the counterion concentration near the surface of the ferroelectric. By controlling the local polarization state of the ferroelectric film, it will be possible to precisely tune the local pH over a very large operating range (i.e. from as low as pH=0 to as high as pH=14). The research approach will employ a combination of characterization tools, including AFM, pH dyes, and self-assembled monolayers to study the local pH above polarized ferroelectric films. Computational techniques will also be developed to compare and interpret the experimental results. If successful, the results of this research will provide an opportunity to create a compact device for synthesizing polypeptide micro-arrays via step and repeat synthesis using pH sensitive Fmoc protective blocking chemistry. Additionally, this research may be used to modulate surface wetting properties, providing an additional degree of control in microfluidic systems. Due to the highly interdisciplinary nature of this work, graduate and undergraduate students will have broad exposure to the fields of electromagnetism, chemistry, biology and computer science. Minority studies from Historically Black College and Universities (HBCU?s) or Historically Minority Universities (HMU?s), will be included in this work for two summer months. In addition, undergraduate students from Duke University will participate in this research through the Duke University Pratt Fellows program.