In the present work, the interaction mechanism of specific polyelectrolyte multilayers (PEMs), fabricated by layer-by-layer deposition of polydiallyldimethylammonium chloride (PDDA) and poly(sodium 4-styrenesulfonate) (PSS), is studied using atomic force microscopy. The underwater oil-repellency of PSS-capped PEMs was further explored by measuring the interaction forces between tetradecane droplets and PEMs-coated silica substrates under various salinities. The force curves were analyzed following the Stokes–Reynolds–Young–Laplace theoretical model. Desirable consistency was achieved between the experimental and theoretical calculations at low NaCl concentrations (0.1 mM and 1 mM); however, underestimation of the attractive force was found as the NaCl concentration increases to moderate (10 mM) and high (100 mM) levels. Discrepancy analyses and incorporated features toward a reduced surface charge density were considered based on the previous findings of the orientation of anionic benzenesulfonate moieties (Liu et al. in Angew Chem Int Ed 54(16):4851–4856, 2015. https://doi.org/10.1002/anie.201411992). Short-range steric hindrance interactions were further introduced to simulate “brush” effect stemming from nanoscale surface roughness. It is demonstrated in our work that the PSS-capped PEMs remains a stable underwater lipophobicity against high salinity, which renders it potential application in surface wetting modification and anti-fouling.

在目前的工作中，使用原子力显微镜研究了聚二烯丙基二甲基氯化铵（PDDA）和聚（4-苯乙烯磺酸钠）（PSS）的逐层沉积制备的特定聚电解质多层膜（PEM）的相互作用机理。通过测量在不同盐度下十四烷液滴与PEMs包覆的二氧化硅基质之间的相互作用力，进一步探索了PSS封端的PEM的水下拒油性。根据斯托克斯-雷诺兹-杨-拉普拉斯理论模型分析了力曲线。在低NaCl浓度（0.1 mM和1 mM）下，实验和理论计算之间达到了令人满意的一致性；然而，当NaCl浓度增加到中等（10 mM）和高（100 mM）时，吸引力被低估了。基于阴离子苯磺酸盐基团取向的先前发现，考虑了差异分析和降低表面电荷密度的合并特征（Liu等人，Angew Chem Int Ed 54（16）：4851-4856，2015。https：// doi.org/10.1002/anie.201411992）。进一步引入了短程空间位阻相互作用，以模拟源自纳米级表面粗糙度的“刷子”效应。在我们的工作中证明，加有PSS的PEM在高盐度下仍保持稳定的水下疏油性，这使其有潜力应用于表面润湿改性和防污垢。//doi.org/10.1002/anie.201411992）。进一步引入了短程空间位阻相互作用，以模拟源自纳米级表面粗糙度的“刷子”效应。在我们的工作中证明，加有PSS的PEM在高盐度下仍保持稳定的水下疏油性，这使其有潜力应用于表面润湿改性和防污垢。//doi.org/10.1002/anie.201411992）。进一步引入了短程空间位阻相互作用，以模拟源自纳米级表面粗糙度的“刷子”效应。在我们的工作中证明，加有PSS的PEM在高盐度下仍保持稳定的水下疏油性，使其具有潜在的表面润湿改性和防污性能。