Surface Modification of Poly(4,4'-oxydiphenilene pyromellitimide) with Low-pressure Plasma Treatment
Graduation Year
2024
Document Type
Thesis
Degree
M.S.
Degree Name
Master of Science (M.S.)
Degree Granting Department
Chemical, Biological and Materials Engineering
Major Professor
Nurettin Sahiner, Ph.D.
Co-Major Professor
Venkat Bhethanabotla, Ph.D.
Committee Member
Ramesh Ayyala, M.D.
Keywords
Bacterial Attachment, Contact Angle, Low-pressure Plasma Treatment, PMDA-ODA, Surface Free Energy, Surface Modifications
Abstract
This study explores the change of the wetting characteristics of commercially availablepolyimide (PI), Kapton® HN, films a type of poly(4,4′-oxydiphenylene-pyromellitimide), following treatment with low-pressure plasmas of carbon tetrafluoride (CF4), air, hydrogen (H2), carbon-dioxide (CO2) and oxygen (O2) gases as well as the surface texturing via laser-exposure procedure. The water contact angle (CA) and surface free energy (SFE) of untreated PI films were determined as 82.4°±0.8 and 45.0±0.3 mN/m, respectively. After CF4 plasma gas treatment, the CA value of PI films increased to 110.2°±1.0, while it decreased to 9.3°±2.3 after O2 plasma gas treatment. The surface free energy (SFE) of PI films was calculated as 79.1±0.5 mN/m and 10.8±0.1 nM/m after the O2 and CF4 plasma gas treatment, respectively. O2 treatment resulted in the most hydrophilic samples.
The effects of multiple successive plasma gas treatments were observed by irradiating the PI surfaces with CF4 and O2 up to six times. Upon multiple plasma treatments of PI films, the CA values shifted to 116.9°±1.1 and 2.2°±0.1, and the SFE value changed to 8.4±0.6 mN/m and 79.8°±0.2 mN/m with CF4 and O2 plasma treatment, respectively. The durability of the surface modification was also observed.
The surface of PI films was textured by creating holes with different sizes of diameters on the samples. The CA values increased up to 121.7°±1.6 and the SFE value decreased down to 9.2±0.7 mN/m after texturing the surface. The combined effect of texturing and CF4 plasma gas treatment made the surface even more hydrophobic resulting in a CA value of 143.6°±2.2 and an SFE value of 1.4±0.3 mN/m.
The kinetic friction force (F||Kinetic) of treated and textured surfaces against water drops was also determined. A notable decrease in F||Kinetic from 277.3±12.5 μN to 177.2±23.6 μN was observed.
Bacterial attachment experiments were conducted with E. coli, P. aeruginosa and S. aureus strains. Significant effects of plasma treatment and surface texturing were reported. The surface of the treated PI films was characterized utilizing ATR-FTIR, XPS and SEM analysis.
This research provides crucial insights into the impact of low-pressure plasma treatment and surface texturing on the wetting properties of PI films, contributing to their improved application across various fields.
Scholar Commons Citation
Aktas, Cihan, "Surface Modification of Poly(4,4'-oxydiphenilene pyromellitimide) with Low-pressure Plasma Treatment" (2024). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/10795
