Graduation Year


Document Type




Degree Name

MS in Materials Science and Engineering (M.S.M.S.E)

Degree Granting Department

Chemical Engineering

Major Professor

Venkat Bhethanabotla, Ph.D.

Co-Major Professor

Scott Campbell, Ph.D.

Committee Member

John Kuhn, Ph.D.


organic vapor sensing, piezoelectric, activity, absorption, adsorption


Quartz crystal microbalances (QCM) are acoustic wave sensor systems which are used majorly for vapor and liquid sensing. QCM come under the category of thickness shear mode (TSM) sensors. There are several methods to study organic vapor sensing; the QCM method is the one that offers the highest sensitivity and generates the most data. Solubilities of benzene, dichloroethane, chloroform and dichloromethane in polyethylene glycol (PEG), polycaprolactone (PCL), and several di-block PEG/PCL copolymers at 298.15 K are reported. There are literature data available for most of the solvents in the homopolymers PEG and PCL but no literature data is available for the copolymers PEG (5000)/ PCL (1000), PEG (5000)/ PCL (5000) and PEG (1000)/ PCL (5000). Activity vs. weight fraction data was collected using a quartz crystal microbalance and are adequately represented by the Flory-Huggins model within experimental error. The data were reported using a QCM in a newly designed flow system constructed in the lab. The working apparatus consisted of a computer loaded with LabVIEW software for data selection, a quartz crystal cell, four bubblers for solvents, a phase lock oscillator, a frequency counter, and a temperature controlled vapor dilution system.

In this thesis, the proof for a working model of the QCM apparatus was reported through a test-case. The test case consists of a study that details the solubility of the polyisobutylene (PIB) polymer in benzene at 298.15 K which was then compared to previous work published in the literature.