Surface fluorination of paper in CF4-RF plasma environments

Plasma-based technologies are an exciting alternative for cellulose and paper modification. Barrier coatings and surface functionalization of cellulose enhances properties and creates new possibilities for cellulose-based products. A parallel plate radio frequency (RF)-plasma reactor was used to modify paper substrates under discharge parameters such as power, time and pressure. Carbon tetrafluoride RF-plasma treatment of paper caused intense fluorination and it was demonstrated that the fluorination reaction mechanisms can be controlled by the external plasma parameters. Fluorine contents as high as 51.3% (contact angle = 147degrees) were obtained for the treated cellulose. It was shown that even treatment times as low as 30 s can generate relative surface fluorine atomic concentrations as high as 30%. High resolution ESCA and ATR-FTIR analysis indicated covalently bound CFx functional groups with CF4 treatment. It was found that under certain experimental conditions super-hydrophobic paper surfaces are created by combining the high surface fluorine atomic concentrations with specific plasma-generated surface topographies.