To shed light on recently explored long-range surface forces generated by subsurface-confined water, the structural characteristics of water molecules penetrating into nanoporous homogeneous and nanograded siloxane plasma polymer films (PPFs) over the time scale of 24 hours are studied by surface-enhanced IR spectroscopy (SEIRAS). Chemically graded PPFs, with embedded hydrophobic-to-hydrophilic gradient, are found to significantly change the average interfacial water orientation due to a unique nanoporous morphology and silanol group coordination. Diffusion of water through the hydrophobic SiO:CH matrix creates an evolution of the coordination of matrix silanol groups, which are eventually deprotonated as soon as the hydration network connects to the aqueous environment. This occurs after ~6 hours of water immersion and coincides with the change of average interfacial water orientation. Both effects are present on hydrophobic samples, but are significantly amplified by the presence of the subsurface vertical amphiphilic gradient (Vgrad), whereas enhanced water uptake in oxygen-plasma modified graded PPFs is covering such effects.

为了阐明近来探索的由地下受限水产生的远程表面力，通过表面增强研究了在24小时内渗透到纳米多孔均质和纳米级硅氧烷等离子聚合物薄膜（PPF）中的水分子的结构特征。红外光谱（SEIRAS）。具有独特的纳米孔形态和硅烷醇基团配位的化学级PPF具有嵌入式的疏水性至亲水性梯度，可显着改变平均界面水取向。水通过疏水性SiO：CH基质的扩散产生了基质硅烷醇基团配位的演变，一旦水合网络连接到水性环境，这些硅烷醇基团最终就会被去质子化。这种现象在浸入水中约6小时后发生，并且与平均界面水取向的变化相吻合。两种作用都存在于疏水性样品上，但由于存在地下垂直两亲梯度（Vgrad）而被显着放大，而氧等离子体修饰的分级PPF中吸水能力的增强则覆盖了这种作用。