Theses and Dissertations
Issuing Body
Mississippi State University
Advisor
Wipf, David
Committee Member
Sygula, Andrezej
Committee Member
Pittman Jr., Charles U.
Committee Member
Zhang, Dongmao
Committee Member
Mlsna, Todd E.
Date of Degree
8-15-2014
Document Type
Dissertation - Open Access
Major
Chemistry
Degree Name
Doctor of Philosophy
College
College of Arts and Sciences
Department
Department of Chemistry
Abstract
Recently, conductive polymer/carbon nanomaterials have drawn attention for use in corrosion inhibition, sensors, energy storage devices, and coatings for electromagnetic shielding applications due to their good mechanical properties and electronic conductivity. Therefore, efforts have been made to find fast and facile methods for the synthesis and development of these hybrids that allow control over key parameters, such as the thickness of the conductive polymer coating. In this study, such hybrids were prepared using polyaniline (PANI) as the conductive polymer and vapor-grown carbon nanofibers (VGCNFs) as the carbon nanomaterial or filler by a semi-dilute in situ polymerization method to be evaluated for their effectiveness as corrosion inhibitory additives to alkyd paints. Spectroscopic, colorimetric, and electric properties of PANI-coated VGCNFs were investigated. The thickness of the PANI coating, along with other parameters, impacts the behavior and mechanisms by which the nanomaterial performs its role in a given application, particularly in the corrosion inhibition processes. Thus, different synthesis conditions, including pretreatment of the nanofibers, the presence of sodium dodecyl sulfate (SDS) surfactant, PreT-VGCNF/ANI ratios (w/w), and polymerization times were tested and their effects on the PANI thickness were microscopically and statistically evaluated. It was found that only different PreT-VGCNF/ANI ratios allowed definite control of the PANI thickness. No clear effect on the thickness was observed after three hours of polymerization. The presence of SDS and pretreatment of VGCNFs displayed a synergistic effect on the appearance and thickness of the PANI film. PANI-coated VGCNF additives, with PANI in the leucoemeraldine base (LEB) and emeraldine base (EB) forms, were synthesized using a PreT-VGCNF/ANI ratio of 0.4 in the presence of SDS. Cold-rolled steel coupons were coated with 20-30 ìm thick alkyd paint coatings, and their electrochemical behavior was investigated by open circuit potential (OCP) and electrochemical impedance (EIS) measurements. The results indicate that, overall, EB/VGCNF additive performed better as a corrosion inhibitor, followed by PreT-VGCNF and LEB/VGCNF additives.
URI
https://hdl.handle.net/11668/19777
Recommended Citation
Cebada-Ricalde, Maria Concepcion, "Synthesis and Characterization of Pani-Coated Vgcnfs and Evaluation of its Use for Corrosion Inhibition" (2014). Theses and Dissertations. 4184.
https://scholarsjunction.msstate.edu/td/4184
Comments
conductivity measurements||colorimetric characterization||TEM||SEM||AFM||UV-vis||ATR-FTIR||Nyquist plots||Bode plots||impedance measurement||open circuit potential measurement