Initiated chemical vapor deposition of poly(1H,1H,2H,2H-perfluorodecyl acrylate) thin films
ABSTRACT A solvent-free initiated chemical vapor deposition (iCVD) process was used to create low surface energy poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) thin films at deposition rates as high as 375 nm/min. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy showed full retention of the fluorine moieties, and no measurable cross-linking was detected. Additionally, the FTIR studies support the hypothesis that film deposition results from vinyl polymerization. For all iCVD PPFDA films, the static contact angle was found to be 120.8 +/- 1.2 degrees. The roughness of the films was found to be between 14.9 and 19.8 nm RMS, and the refractive index of the films was found to be between 1.36 and 1.37. The deposition rate was studied as a function of the substrate temperature and the partial pressure of the monomer. It was found that the deposition rate increases with decreasing substrate temperature and increasing monomer partial pressure. It was also found that the molecular weight increases with decreasing substrate temperature and increases with increasing monomer partial pressure. The highest molecular weight measured was 177 300 with a polydispersity of 2.27. Quartz crystal microbalance (QCM) measurements showed that these effects correlated with an increased monomer concentration at the surface. The deposition rate data and the QCM data were quantitatively analyzed to find the rate constants of the process using a previously published model for the iCVD process involving nonfluorinated monomers. The determined values of the rate constants of the surface polymerization were found to be similar to the rate constants measured in liquid-phase free radical polymerization. The kinetic data found in this paper can now be used to study iCVD deposition onto substrates with more complex geometries.
- SourceAvailable from: Anna Maria Coclite[Show abstract] [Hide abstract]
ABSTRACT: Preferred crystallographic orientation (texture) in thin films frequently has a strong effect on the properties of the materials and it is important for stable surface properties. Organized molecular films of poly-perfluorodecylacrylate p(PFDA) were deposited by initiated Chemical Vapor Deposition (iCVD). The high tendency of p(PFDA) to crystallize has been fully retained in the polymers prepared by iCVD. The degree of crystallinity and the preferred orientation of the perfluoro side chains, either parallel or perpendicular to the surface, were controlled by tuning the CVD process parameters (i.e. initiator to monomer flow rate ratio, filament temperature, and substrate temperature). Super- hydrophobicity (advancing water contact angle, WCA, of 160°, low hysteresis of 5°), and oleophobicity (advancing CA with mineral oil of 120°) were achieved. Low hysteresis was associated with high crystallinity, particularly when the orientation of the crystallites resulted in the perfluoro side groups being oriented parallel to the surface. The latter texture resulted in smoother film (RMS roughness < 30 nm) than the texture with the chains oriented perpendicularly to the surface. This can be very advantageous for applications that require smooth but still crystalline films.Physics Procedia 12/2013; 46:56-61. DOI:10.1016/j.phpro.2013.07.045
- [Show abstract] [Hide abstract]
ABSTRACT: The ability to pattern porous materials with functional polymeric coatings is important for the fabrication of next-generation microfluidic platforms, membranes, tissue scaffolds, and optical devices. Here, we demonstrate for the first time that solventless initiated chemical vapor deposition (iCVD) can be used for three-dimensional patterning of porous substrates. The individual fibers of hydrophilic chromatography paper were uniformly coated with a thin layer of hydrophobic photoresponsive poly(o-nitrobenzyl methacrylate) (PoNBMA). X-Ray photoelectron spectroscopy and contact angle measurements confirmed that the PoNBMA coating penetrated the entire depth of the paper and scanning electron microscope images confirmed that the porosity and hierarchical structure of the paper were retained during the coating process. The PoNBMA coating was then patterned through the entire depth of the paper by exposure to ultraviolet light followed by rinsing in biologically compatible buffer. We demonstrated the utility of our patterning process by fabricating three-dimensional hydrophilic and hydrophobic regions into the chromatography paper for use as paper-based microfluidic devices. Our patterning process represents an environmentally friendly method to pattern three-dimensional materials since no organic solvents are used during the polymerization process or patterning step.Soft Matter 03/2011; 7(6):2428-2432. DOI:10.1039/C0SM01214A · 4.15 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: A robust superhydrophobic fabric was achieved by depositing a stacked polymer film composed of a poly(1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane) (p(V4D4)) layer and a poly(1H,1H,2H,2H-perfluorodecylacrylate) (p(PFDA)) layer. The polymer film was deposited by initiated chemical vapor deposition (iCVD), a solventless process that allows conformal coating of the stacked polymer film on various micro-structured substrates. The two polymeric layers most likely formed a covalent bonding at their interface, and thus the stacked polymer film was characterized by both strong hydrophobicity and enhanced mechanical robustness originated from highly cross-linked p(V4D4) and p(PFDA). The surface topography of superhydrophobic coating was systematically tunable by controlling the operating parameters of iCVD process and a hierarchical structure was obtained by a simple one-step iCVD process. The film was also highly transparent in the wavelength range from 380 nm to 780 nm. Fabrics coated with this stacked polymer film displayed chemical robustness even after exposure to different chemicals including acetone, toluene, H2SO4, and KOH. The fabric also maintained its water repellency even after 20000 cycles of the abrasion test and after 75 cycles of the laundry test.02/2013; 4(5):1664-1671. DOI:10.1039/C2PY20963B