Relationships between surface chemistry, nanotopography, wettability and ice adhesion in epoxy and SU-8 modified with fluoroalkylsilanes from the vapor phase
Relationships between surface chemistry, nanotopography, wettability and ice adhesion in epoxy and SU-8 modified with fluoroalkylsilanes from the vapor phase
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DOI：
10.1016/j.apsusc.2019.02.082
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发表时间：
2019-06
影响因子：
6.7
通讯作者：
M. Psarski;D. Pawlak;J. Grobelny;Grzegorz Celichowski
中科院分区：
文献类型：
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作者：
M. Psarski;D. Pawlak;J. Grobelny;Grzegorz Celichowski
这项工作的目的是阐明冰附着在固体基质上是如何与表面润湿性相关的，而表面润湿性又是由表面化学成分和纳米形貌决定的。该研究是用环氧树脂和SU-8（一种负性环氧基光刻胶）的微观光滑表面进行的。环氧树脂以其优异的物理化学性能而闻名。它们通常用作户外设备的表面涂层，并且可以面对恶劣的环境条件，例如结冰。SU-8广泛用于表面形貌结构的微加工。其中一些结构被设计成超疏水的，在某些情况下，是恐冰的。在本研究中，我们重点研究了这些材料的表面物理化学修饰在控制其润湿和结冰性能中的作用。在一个分子中含有3、8、10和12个碳原子的同源氟烷基硅烷（FAS）系列，被用来使环氧和SU-8表面疏水。在常压（AP-VPD）下从气相沉积FAS。由于在氧射频（RF）等离子体中蚀刻和随后的硅烷化，改性的衬底表面纳米粗糙度显着增加。AP-VPD获得的涂层由于在沉积过程中有大量的FAS蒸气和大气水而导致表面粗糙度增加。这种条件有利于垂直聚合和簇状矿床的形成。结果表明，纳米粗糙度会影响改性表面的润湿性。研究了FAS主链长度对表面纳米形貌的影响及其对表面润湿性的影响。最后，研究了润湿性与冰附着之间的关系。在拉伸模式下研究了冷冻液滴与改性基板之间的粘附强度。结果表明，冰-基质黏附强度与水-基质黏附的宏观功呈线性相关。
The objective of this work was to elucidate how ice adhesion to solid substrates is related to surface wettability, which, in turn, results from surface chemical composition and nanotopography. The study was carried out using microscopically smooth surfaces of epoxy and SU-8, a negative epoxy-based photoresist. Epoxy resins are known for their outstanding physicochemical properties. They are often used as surface coatings for outdoor devices and can face harsh environmental conditions, such as icing. SU-8 is extensively used in microfabrication of surface topographical structures. Some of these structures are designed to be superhydrophobic and, in some cases, icephobic. In the present study, we focused on the role of surface physicochemical modifications of these materials in controlling their wetting and icing properties. A homologous series of fluoroalkyl silanes (FAS), which contained 3, 8, 10, and 12 carbon atoms in a molecule, was used to make epoxy and SU-8 surfaces hydrophobic. The FAS deposition process was carried out from vapor phase at atmospheric pressure (AP-VPD). The modified substrates exhibited a significantly increased surface nanoroughness, as a result of etching in oxygen radio frequency (RF) plasma and subsequent silanization. The coatings obtained by the AP-VPD contribute to surface roughness because the FAS vapors and atmospheric water are abundant during deposition processes. Such conditions favor vertical polymerization and formation of clustered deposits. The resulting nanoroughness was shown to affect wettability of modified surfaces. The influence of FAS backbone chain length on resulting surface nanotopography and how it affects surface wettability was investigated. Finally, the relationship between wettability and ice adhesion was examined. The strength of adhesion between frozen sessile droplets and modified substrates was investigated in tensile mode. A linear correlation between the ice-substrate adhesion strength and the macroscopic work of water-substrate adhesion was found.