College of Engineering and Polymer Science

Date of Last Revision

2024-06-04 07:24:29


Chemical Engineering

Honors Course


Number of Credits


Degree Name

Bachelor of Science

Date of Expected Graduation

Spring 2024


The purpose of this project was to understand the relationship between relative humidity, ion valency, and the structure of water on positively (PMETAC) and negatively (PSPMA) charged polyelectrolyte brushes. The polyelectrolyte brushes were synthesized using Activators Regenerated by Electron Transfer Atom Transfer Radical Polymerization (ARGET ATRP) and were soaked in concentrations containing 0.1 M of the target counterion. The brushes were then exposed to humid vapor, and spectra were collected in 5% intervals between 0% and 85% for each counterion. Two trials were completed for each counterion studied to ensure agreement between datasets. In all spectra, peaks appeared for the carbonyl group and OH bonding. Each water peak was divided into three types of water based on the location, ice-like (3061 to 3265 cm-1) , liquid-like (3265 to 3520 cm-1) , and free (3500 to 3742 cm-1). It was observed that as humidity increased, the water peak present at approximately 3400 cm-1 increased in intensity and shifted towards lower wavenumbers, indicating a more strongly bonded ice-like water structure at high humidity. Multivalent counterions produced twice the fraction of ice-like water compared to monovalent ions, demonstrating a difference in both water absorbance and structure when multivalent counterions are present.

Research Sponsor

Dr. Ali Dhinojwala

First Reader

Dr. Fardin Khabaz

Second Reader

Dr. Kevin Cavicchi

Honors Faculty Advisor

Dr. Donald Visco

Proprietary and/or Confidential Information




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