Surface Properties of Poly[2-perfluorooctyl)ethyl acrylate] Deposited from Liquid CO2 High-Pressure Fee Meniscus Coating
The surface characteristics of poly[2-(perfluorooctyl)ethyl acrylate] (PFOEA) films deposited using a high-pressure free meniscus coating (hFMC) process with liquid CO{sub 2} (l-CO{sub 2}) as the coating solvent on 12.5 cm diameter silicon wafer substrates were investigated using contact angle measurements, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy. The results were compared with surface property measurements of PFOEA films deposited from 1,1,2-trichlorotrifluoroethane (Freon 113) under normal dip coating conditions at atmospheric pressure. NEXAFS measurements showed that perfluoroalkyl groups in the films from l-CO{sub 2} and Freon 113 were well-organized and oriented normal to the substrate at the air/polymer interface. AFM images and XPS measurements revealed that a terrace-like structure of the PFOEA film from l-CO{sub 2} resulted in carbonyl group exposure at the air/polymer interface. This leads to smaller contact angles on the films cast from l-CO{sub 2} relative to the specimens deposited from Freon 113. Annealing the films deposited from the solvents resulted in droplet formation on the surface due to dewetting. The critical surface tension ({gamma}{sub c}) after annealing the film prepared from Freon 113 increased from 6.5 to 8.5 mJ/m{sup 2}, whereas {gamma}{sub c} of the film deposited from l-CO{sub 2} decreased slightly from 9.7 to 8.9 mJ/m{sup 2}. We discuss how surface morphology changes before and after annealing play a role in the variation of {gamma}{sub c}.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 930318
- Report Number(s):
- BNL-81028-2008-JA; TRN: US200822%%1257
- Journal Information:
- Macromolecules, Vol. 40
- Country of Publication:
- United States
- Language:
- English
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