Modifying Surfaces with the Primary and Secondary Faces of Cyclodextrins To Achieve a Distinct Anti-icing Capability
Modifying Surfaces with the Primary and Secondary Faces of Cyclodextrins To Achieve a Distinct Anti-icing Capability
复制标题
用环糊精的主面和副面改性表面以实现独特的防冰能力
DOI：
10.1021/acs.langmuir.9b00284
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发表时间：
2019
期刊：
影响因子：
3.9
通讯作者：
Wang Jianjun
中科院分区：
文献类型：
--
作者：
Cheng Qi;Jin Shenglin;Liu Kai;Xue Han;Huo Bingchen;Zhou Xin;Wang Jianjun
有机物诱导的冰成核（HIN）是低温生物学和大气物理学等领域的一个长期研究课题，但由于对HIN的机理认识不清，至今仍制约着对HIN的控制。在这项工作中，通过实验研究用环糊精（CD）的主面（PF）和次面（SF）改性的表面上的HIN行为（即，α-1，4-linkeddd-（+）-吡喃葡萄糖，具有两个相对平坦的羟基化面）。为了实现这一点，首先通过将CD的PF和SF选择性地结合到固体表面上来将CD固定到表面;因此，PF或SF暴露于液态水。有趣的是，HIN温度和延迟时间测定表明，当CD的PF（其与冰晶格匹配）暴露于液态水时，HIN被抑制，而当CD的SF（其与冰晶格不匹配）暴露于液态水时，HIN被促进。这偏离了通常认为具有冰晶格匹配模板的表面促进HIN的想法。相反，1H NMR研究表明，由于分子内氢键的形成，CD的SF中的羟基（OH）的共振最去屏蔽，与CD的PF中的OH相比，这削弱了SF上的OH基团与水分子之间的相互作用。因此，不同的防冰能力的PF和SF的CD可以实现和建立由不同的OH基团之间的相互作用的两个面和水，这是具有很大的实际应用潜力。表面与水分子之间的分子水平相互作用可能是预测材料HIN能力的一个更合适的标准。
Heterogenous ice nucleation (HIN) induced by organic materials is a long-lasting issue in wide-ranging fields from cryobiology to atmospheric physics, but efforts for controlling HIN are still restricted by incomplete understanding of its mechanism. In this work, distinct anti-icing capabilities were achieved by experimentally investigating the HIN behavior on the surfaces modified with the primary face (PF) and secondary face (SF) of cyclodextrins (CDs) (i.e., α-1,4-linkedd-(+)-glucopyranose with two relatively flat and hydroxylated faces). To achieve this, CDs were first immobilized to the surfaces through selectively binding the PF and SF of CDs onto the solid surfaces; as such, either PF or SF is exposed to liquid water. Interestingly, HIN temperature and delay time assays indicate that HIN is depressed when the PF of CDs (which matches with the ice lattice) is exposed to liquid water whereas the HIN is facilitated when the SF of CDs (which mismatches with the ice lattice) is exposed to liquid water. This deviates from the common thought that surfaces with a template of ice lattice match facilitate the HIN. Instead,1H NMR studies show that the resonances of hydroxyl (OH) in the SF of CDs are most deshielded due to the formation of intramolecular hydrogen bonds, in comparison to that of OH in the PF of CDs, which weakens the interaction between the OH groups on the SF and water molecules. Thus, the distinct anti-icing capabilities of the PF and SF of CDs can be achieved and established by the distinct interactions between OH groups on the two faces and water, which is of great potential for practical applications. The molecular-level interactions between surfaces and water molecules may be a more appropriate criterion for forecasting materials’ HIN ability.