Herein we present a study on the formation of irreversibly adsorbed layer of polystyrene molecules on silicon oxide surfaces. Various scanning probe microscopy techniques have been employed to study both the morphology and the mechanical properties of these self‐assembled thin polymeric layers. More in detail, standard contact mode, force versus distance spectroscopy and ultrasonic force microscopy have been employed to obtain spatially‐resolved maps and, thus, observe the physisorption of polystyrene on native silicon oxide substrate in function of time. Thick films, spin coated from a toluene solution, have been annealed at a temperature above the glass transition for increasing time intervals, and finally thoroughly rinsed in toluene. We have found that isolated islands of adsorbed chains are already present after an annealing time of half an hour. Prolonged annealing determines a progressive increase of the covered areas, whereas the formation of a complete flat layer requires 24 h. The pattern observed is in line with expected evolution of an unstable system, corresponding to the phenomenon of spinodal dewetting. Adhesion measurements show that the films present a reduced snap‐off and the formation of a meniscus between tip and surface for annealing time up to 8 h. On the other hand, elastic measurements allow us to observe a progressive increase of the elastic modulus, with a complete transition for annealing time above 20 h. This is indication that a dense packing of the polystyrene molecules occurs, in line with the predictions of current models on the kinetics of irreversible adsorption.

中文翻译：

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氧化硅上聚苯乙烯吸附层的形态和弹性转变

在此，我们对氧化硅表面上聚苯乙烯分子不可逆吸附层的形成进行了研究。各种扫描探针显微镜技术已被用于研究这些自组装薄聚合物层的形态和机械性能。更详细地说，标准接触模式、力与距离谱和超声力显微镜已被用于获得空间分辨图，从而观察聚苯乙烯在天然氧化硅衬底上随时间的物理吸附。从甲苯溶液旋涂的厚膜已在高于玻璃化转变温度的温度下退火并延长时间间隔，最后在甲苯中彻底冲洗。我们发现在半小时的退火时间后，吸附链的孤立岛已经存在。长时间的退火决定了覆盖区域的逐渐增加，而完整平坦层的形成需要 24 小时。观察到的模式与不稳定系统的预期演变一致，对应于旋节线去湿现象。附着力测量表明，在长达 8 小时的退火时间内，薄膜呈现出减少的折断和尖端和表面之间弯月面的形成。另一方面，弹性测量使我们能够观察到弹性模量的逐渐增加，退火时间超过 20 小时时完全转变。这表明聚苯乙烯分子发生了密集堆积，