Langmuir monolayer and Langmuir-Blodgett films formed by a melamine-headed azobenzene-derived amphiphile: interfacial assembly affected by host-guest interaction.
Langmuir monolayer and Langmuir-Blodgett films formed by a melamine-headed azobenzene-derived amphiphile: interfacial assembly affected by host-guest interaction.
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DOI：
10.1021/la8039708
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发表时间：
2009-02
期刊：
影响因子：
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通讯作者：
Weihong Xu;Yanhua Wang;Y. Xiao;Fang Liu;Guoyuan Lu
中科院分区：
文献类型：
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作者：
Weihong Xu;Yanhua Wang;Y. Xiao;Fang Liu;Guoyuan Lu
合成了一种新的偶氮苯衍生的三聚氰胺头部两亲分子2Azo-2C12H2-三聚氰胺。π-A等温线的测量表明，该两亲物在纯水和含巴比妥酸（BA）或胸腺嘧啶（T）的亚相中均能形成稳定的Langmuir单分子膜。其单分子膜在纯水上的崩溃表面压力和极限分子面积分别为40 mN/m和0.56 nm~2。当在亚相中引入巴比妥酸或胸腺嘧啶时，相应的π-A等温线表现出较低的坍塌表面压（BA为22 mN/m，T为21 mN/m）和较小的极限分子面积（BA为0.54 nm 2，T为0.52 nm 2）。对2Azo-2C_（12）H_（25）-三聚氰胺形成的LB膜进行了UV-vis和FT-IR研究。结果表明，从纯水沉积的2Azo-2C12H25-三聚氰胺的LB膜在UV照射下经历明显的H-聚集体的崩溃，而从含BA或T的亚相沉积的LB膜保留H-聚集体。主客体相互作用引起的偶氮苯光异构化的阻断应该是稳定的H-聚集体的原因。在含BA或T的亚相上形成的Langmuir单分子膜中，提出了形成线性超分子聚合物链的1：1主体/客体结合模式。目前的研究结果表明，主客体相互作用应该是一种有效的手段来操纵偶氮苯衍生的两亲物的界面组装。
A novel azobenzene-derived amphiphile with a melamine head, 2Azo-2C12H2-melamine, has been synthesized. pi-A isotherm measurements displayed that this amphiphile is able to form a stable Langmuir monolayer on both pure water and barbituric acid (BA)- or thymine (T)-containing subphases. The collapse surface pressure and limiting molecular area of its Langmuir monolayer on pure water are 40 mN/m and 0.56 nm2, respectively. However, when barbituric acid or thymine was introduced into the subphase, the corresponding pi-A isotherms of the monolayers exhibited a lower collapse surface pressure (22 mN/m for BA, 21 mN/m for T) and smaller limiting molecular area (0.54 nm2 for BA and 0.52 nm2 for T). UV-vis and FT-IR studies of the LB films formed by 2Azo-2C12H25-melamine have also been carried out. The results indicated that the LB films of 2Azo-2C12H25-melamine deposited from pure water undergo distinct collapse of the H-aggregate upon UV irradiation, while the LB films deposited from a BA- or T-containing subphase retain the H-aggregate. The host-guest-interaction-induced blockage of azobenzene photoisomerization should be responsible for the stabilized H-aggregate. A 1:1 host/guest binding mode to form a linear supramolecular polymeric chain has been proposed in the Langmuir monolayers formed on a BA- or T-containing subphase. The current results suggest that the host-guest interaction should be an effective means to manipulate the interfacial assembly of azobenzene-derived amphiphiles.