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

To introduce superior performance such as great oil and water repellency, and so forth onto wood surfaces without damaging its sense of touch 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 surfaces, whereas the carbon and oxygen atoms were decreased, resulting in a significant improvement of the oil and water repellency without changes in the appearances of the woods so far as could be observed by the naked eye and touched by hand. 2) Fluorine-containing functional groups on the surface were shown to be CF3, CF2 and CF from the curve-resolved components of C1S ESCA (Electron Spectroscopy for Chemical Analysis) spectra. In addition, some of the curve-resolved components indicated the existence of newly added oxygen atoms. 3) To avoid oxygen plasma making wood surfaces hydrophilic, it is necessary for pretreatment to dry the samples in an oven and to deair them in an apparatus prior to CF4 plasma discharge, because water repellency is greatly dependent 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.