Morphological and Chemical Effects of Plasma Treatment with Oxygen (O2) and Sulfur Hexafluoride (SF6) on Cellulose Surface

Cellulose is a polymer widely available in nature, however its applications may be restrict due to its hydrophilic character. The creation of hierarchical structures on the surface is one of the required factors to obtain the hydrophobicity of this material. In order to compare the morphological and chemical effects caused by the action of different gases in the creation of nanostructures on the cellulose surface, samples were exposed to oxygen (O2) and sulfur hexafluoride (SF6) plasma treatments. The changes in morphology after treatment prove that both the gases were able to create similar nanostructures in the material. The analysis of elemental composition and identification of functional groups on the sample surface showed that chemical modifications occurred differently for each treatment. Contact angle measurements revealed that samples treated by O2 plasma remained hydrophilic, whereas low receptivity to polar (θ > 120º) and non-polar (θ > 100º) liquids was observed for samples exposed to SF6 plasma.

纤维素（Cellulose）是广泛存在于自然界的聚合物，但其亲水特性会限制其应用范围。在材料表面构建分级结构（hierarchical structures），是赋予该材料疏水性（hydrophobicity）的必要条件之一。为对比不同气体等离子体处理在纤维素表面制备纳米结构（nanostructures）时所产生的形貌与化学效应，本研究将样品分别置于氧气（O₂）与六氟化硫（SF₆）等离子体环境中进行处理。经处理后的形貌表征结果证实，两种气体均可在材料表面制备出结构相似的纳米结构。对样品表面的元素组成分析与官能团（functional groups）鉴定结果显示，两种处理所引发的化学改性过程存在显著差异。接触角测量结果表明，经氧气等离子体处理的样品仍保持亲水特性；而经六氟化硫等离子体处理的样品则对极性（接触角θ＞120°）与非极性（接触角θ＞100°）液体均表现出较低的接纳性。