Oxygen plasma treatment was applied to atomically flat quartz surfaces in order to study the effect of surface activity on the adsorption of a silyl anchored quaternary ammonium salt biocide. Reduction of contact angle of the quartz surfaces were achieved from 72° to between 14° and 20° by applying oxygen plasma at increasing power between 100 W and 500 W. XPS analysis of the plasma-treated quartz surfaces indicated an increase in the presence of oxygen, implying the conversion of quartz surface siloxane groups into surface hydroxyl groups, consistent with the reduction in contact angle. Surfaces were examined by AFM after adsorption of silyl anchoring quaternary ammonium salts (AQAS). The surface profile of samples indicated an increase in the thickness of the adsorbed AQAS layer from 2.9 ± 0.1 nm for pristine quartz surfaces to 19.0 ± 2.0 nm for oxygen plasma treated surfaces, which is approximately the vertical dimension of 6 oriented molecular layers. The covalently bonded AQAS layer on the quartz surface exhibits a discontinuous film structure consisting of micro-zones of AQAS layers separated by voids or gaps, defined as regions on the quartz surface free of bound AQAS layers. These zones and voids are a consequence of the varying hydrophilicity/adsorption capability of the quartz surface. Plasma treated surfaces also showed a 3-fold reduction of void dimension from 3 µm to 1 µm between the AQAS adsorbed zones on the quartz slide owing to the increased hydrophilicity and adsorption capability of the surface. A leaching study of the AQAS adsorbed-quartz surfaces resulted in the reduction of film thickness from 19.0 ± 2.0 nm to 8 ± 1.0 nm. This reduction indicates the removal of some loosely bound outer layers, but confirms the retention of the surface-anchored layer of AQAS as well as a second and perhaps third layer adsorbed on the anchored first layer.

将氧等离子体处理应用于原子级平坦的石英表面，以研究表面活性对甲硅烷基锚定季铵盐杀生物剂吸附的影响。通过以 100 W 和 500 W 之间增加的功率施加氧等离子体，使石英表面的接触角从 72° 减小到 14° 和 20° 之间。等离子体处理的石英表面的 XPS 分析表明，在氧，这意味着石英表面硅氧烷基团转化为表面羟基，与接触角的减小一致。在吸附甲硅烷基锚定季铵盐 (AQAS) 后通过 AFM 检查表面。样品的表面轮廓表明吸附 AQAS 层的厚度从原始石英表面的 2.9 ± 0.1 nm 增加到 19.0 ± 2。0 nm 用于氧等离子体处理的表面，这大约是 6 个定向分子层的垂直尺寸。石英表面共价键合的 AQAS 层表现出不连续的膜结构，由空隙或间隙分隔的 AQAS 层微区组成，定义为石英表面上没有结合 AQAS 层的区域。这些区域和空隙是石英表面亲水性/吸附能力不同的结果。由于表面的亲水性和吸附能力增加，等离子处理的表面也显示出石英载玻片上 AQAS 吸附区之间的空隙尺寸从 3 µm 减少到 1 µm 的 3 倍。AQAS 吸附石英表面的浸出研究导致薄膜厚度从 19.0 ± 2.0 nm 减少到 8 ± 1.0 nm。