Plasma surface functionalization of poly[bis(2,2,2-trifluoroethoxy)phosphazene] films and nanofibers.

Polyphosphazenes are a class of hybrid organic-inorganic macromolecules with high thermo-oxidative stability and good solubility in many solvents. Fluoroalkoxy phosphazene polymers also have high surface hydrophobicity. A method is described to tune this surface property while maintaining the advantageous bulk materials characteristics. The polyphosphazene single-substituent polymer, poly[bis(2,2,2-trifluoroethoxy)phosphazene], with flat film, fiber mat, or bead mat morphology was surface functionalized using an atmospheric plasma treatment with oxygen, nitrogen, methane, or tetrafluoromethane/hydrogen gases. Surface chemistry changes were detected by static water contact angle (WCA) measurements as well as X-ray photon spectroscopy (XPS). It was found that changes in the WCA of as much as 150 degrees occurred, accompanied by shifts in the ratio of elements on the polymer surface as detected by XPS. Overall this plasma technique provides a convenient method for the generation of specific surface characteristics while maintaining the hydrophobicity of the bulk material.

Decomposition reaction of organophosphorus nerve agents on solid surfaces with atmospheric radio frequency plasma generated gaseous species.

The decomposition and detoxification of compounds are of great interest in environmental protection and defense-related areas. We report the generation of gaseous excited species by scanning atmospheric radio frequency (rf) plasma and their reactions with two representative organophosphorus nerve agents, paraoxon and parathion, deposited on solid surfaces. The excited gaseous species generated in the Ar and Ar/O2 plasma were identified as atomic oxygen, OH radical, and excited nitrogen molecule from optical emission spectroscopy analysis. The reaction of these species with paraoxon and parathion was monitored with reflection-absorption infrared spectroscopy and compared with the decomposition by UV irradiation and UV/ozone treatments. The decomposition products of the atmospheric rf plasma treatment were similar to those of the UV/ozone treatment. The atomic oxygen and excited OH species generated by the plasma appear to be responsible for the oxidation of paraoxon and parathion. The plasma-induced decomposition process was much faster and more efficient than the UV/ozone process. The complete detoxification of paraoxon and parathion upon a short time exposure to the Ar/O2 plasma was confirmed by the Drosophila melanogaster culture test.

Superhydrophobic CFx coating via in-line atmospheric RF plasma of He-CF4-H2.

Stable superhydrophobic coatings on various substrates are attained with an in-line atmospheric rf plasma process using CF4, H2, and He. The coating layer is composed of CFx nanoparticulates and has an average roughness of approximately 10 nm. This roughness is much smaller than other surfaces reported for superhydrophobicity in the literature. The superhydrophobic coatings are produced on both metallic and insulating substrates without any need of separate microroughening or vacuum lines.