SURFACE MODIFICATION OF WOOD IN FLUORINE-CONTAINING GAS PLASMA .1. TETRAFLUOROMETHANE PLASMA TREATMENT

To introduce superior performance such as great oil and water repellen cy, and so forth onto wood surfaces without damaging its sense of touc h and beauty, woods were treated with tetrafluoromethane (CF4) plasma in various states. The results obtained were as follows: 1) In a very short treatment time, many fluorine atoms were added onto the wood sur faces, whereas the carbon and oxygen atoms were decreased, resulting i n a significant improvement of the oil and water repellency without ch anges in the appearances of the woods so far as could be observed by t he naked eye and touched by hand. 2) Fluorine-containing functional gr oups on the surface were shown to be CF3, CF2 and CF from the curve-re solved components of C1S ESCA (Electron Spectroscopy for Chemical Anal ysis) spectra. In addition, some of the curve-resolved components indi cated the existence of newly added oxygen atoms. 3) To avoid oxygen pl asma making wood surfaces hydrophilic, it is necessary for pretreatmen t to dry the samples in an oven and to deair them in an apparatus prio r to CF4 plasma discharge, because water repellency is greatly depende nt on the existence of oxygen atoms in the apparatus. 4) The modified surface layers of the samples were considerably stable, and they still had great water repellency after soaking them in water.