The blooming of sodium dodecyl sulfate (SDS) and the influence of plasticizer (glycerol) on the surfactant distribution in poly(vinyl alcohol) (PVA) films have been explored by neutron reflectometry (NR) and ion beam analysis techniques. When in binary films with PVA, deuterated SDS (d₂₅-SDS) forms a surface excess corresponding to a wetting layer of the surfactant molecules at the film surface. The magnitude of this surface excess increased significantly in the presence of the plasticizer, and the surfactant was largely excluded from the PVA subphase. NR revealed smectic nanostructures for both SDS and glycerol components within this surface excess in plasticized films. This combined layer comprises surfactant lamellae, separated by interstitial glycerol-rich layers, which is only formed in the plasticized films and persists throughout the surface excess. Atomic force microscopy micrographs of the film surfaces revealed platelike structures in the plasticized PVA, which were consistent with the rigid defects in the surfactant-rich lamellae. The formation of these structures arises from the synergistic surface segregation of SDS and glycerol, evidenced by surface tensiometry. Cloud point analysis of bulk samples indicates a transition at ∼55% water content, below which phase separation occurs in ternary films. This transition is likely to be necessary to form the thick wetting layer observed and therefore indicates that film components remain mobile beyond this point in the drying process.

中文翻译：

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自旋流延聚乙烯醇薄膜上的近交表面活性剂/增塑剂层的起霜

通过中子反射法（NR）和离子束分析技术，探索了十二烷基硫酸钠（SDS）的起霜和增塑剂（甘油）对聚乙烯醇（PVA）膜中表面活性剂分布的影响。当使用PVA制成二元胶卷时，氘代SDS（d ₂₅（-SDS）形成表面过量，其对应于膜表面上的表面活性剂分子的润湿层。在增塑剂的存在下，这种表面过量的量显着增加，并且表面活性剂在很大程度上被排除在PVA亚相之外。NR揭示了增塑膜中该表面过量的SDS和甘油组分的近晶纳米结构。该结合层包括由富含间隙甘油的层隔开的表面活性剂薄片，其仅在增塑膜中形成并且在整个表面过量处持续存在。薄膜表面的原子力显微镜照片显示了增塑的PVA中的板状结构，这与富含表面活性剂的薄片中的刚性缺陷是一致的。这些结构的形成源自SDS和甘油的协同表面分离，这由表面张力测定法证明。散装样品的浊点分析表明，在〜55％的水含量下有一个过渡，低于该过渡时，三元膜会发生相分离。这种转变可能是形成观察到的较厚的润湿层所必需的，因此表明在干燥过程中，薄膜成分在此点之外仍保持活动状态。