Doctoral Dissertations


Zhe-Fei Li


"A one-step synthesis technique has been used to fabricate sensors by growing polyaniline nanofibers and polyaniline/metal nanocomposites in the active area of an interdigitated electrode array. Polyaniline nanofiber sensors can be fabricated by irradiating an aqueous precursor solution containing aniline, HCl, a metal salt, and ammonium persulfate (APS) with a high pressure Hg lamp. The sensors are ready for operation after polymerization is complete, and no additional processing steps are necessary. These sensors showed faster and more intensity response to various organic vapors than conventional bulk polyaniline sensors due to their larger surface area. A chemisorption model and a diffusion model were used to fit the sensor response of nanostructured polyaniline sensors. Both models can mathematically fit the sensor response as a function of time. Fitting errors from the two models were in a reasonable range, both allowing reasonable mathematical forms for the time-dependent and concentration behavior.

An oligomer-assisted polymerization method was carried out to synthesize polythiophene nanofibers. In this approach, a solution of thiophene, FeCl₃, and terthiophene was dissolved in acetonitrile. Compared to conventional chemical polymerization, a polythiophene oligomer, terthiophene or bithiophene, was added to assist the formation of nanofibers. The polythiophene collected after the 12 h reaction time was found to have nanofibrilar morphology with an average diameter of about 40-50 nm. Unlike other hard-template or soft-template techniques, this method does not require the introduction of a heterogeneous phase"--Abstract, page iv.


Blum, Frank D.

Committee Member(s)

Van-De-Mark, Michael R.
Kim, Chang-Soo
Schwartz, Robert W.
Miller, F. Scott, 1956-


Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering


National Science Foundation (U.S.)


Missouri University of Science and Technology

Publication Date

Fall 2010

Journal article titles appearing in thesis/dissertation

  • One-step fabrication of a polyaniline nanofiber gas sensor
  • Amplified response and enhanced selectivity of metal-pani fiber composite sensors
  • Modeling of the response of nanostructured polyaniline gas sensors
  • Templateless route to polythiophene nanofibers: effect of synthetic conditions and mechanism of formation


xvi, 139 pages

Note about bibliography

Includes bibliographical references.


© 2010 Zhefei Li, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Conducting polymers
Nanostructures -- Transport properties

Thesis Number

T 9701

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Electronic OCLC #