Department of Chemistry, Martin Luther University Halle-Wittenberg, D-06099 Halle (Saale), Germany.
J Colloid Interface Sci. 2009 Dec 15;340(2):276-84. doi: 10.1016/j.jcis.2009.08.046. Epub 2009 Sep 8.
New 1-acyl-1,2,4-triazoles (ATs) with different n-alkyl chain lengths from C2 to C18 were synthesized. ATs with long n-alkyl chains (C12 and larger) are non-charged amphiphilic molecules with a polar triazole head group. The Langmuir isotherms of ATs at the air-water interface with 12 (DoT-C12), 14 (MyT-C14), 16 (PaT-C16) and 18 (StT-C18) carbon atoms in their n-alkyl chains were studied using surface pressure-mean molecular area (pi-mmA) measurements. Characteristic for the Langmuir isotherms of PaT-C16 and StT-C-18 was the first sharp increase of the surface pressure at a mmA value of approximately 20A(2) marking a transition of the ATs from the gaseous state with n-alkyl chains already oriented perpendicular to the water surface to a condensed state. The collapse of the monolayers occurred between 20 and 36mNm(-1) with a typical 'spike' in the isotherms of MyT-C14, PaT-C16 and StT-C18 which can be assigned to the buckling and subsequent folding of the monolayer. After the collapse point a pseudo-plateau region of slightly increasing surface pressure appeared for all ATs from C12 to C18 indicating a trilayer formation by the roll-over mechanism for MyT-C14, PaT-C16 and StT-C18. Upon further compression the final collapse occurred at pi values between 59 and 67mNm(-1). From reversibility studies it was found that the Langmuir isotherms of the ATs were irreversible. The morphology of Langmuir-Blodgett films of ATs transferred onto silicon wafers was studied by atomic force microscopy.
新型 1-酰基-1,2,4-三唑（ATs），具有从 C2 到 C18 的不同 n-烷基链长度。具有长 n-烷基链（C12 及以上）的 ATs 是不带电荷的两亲性分子，具有极性三唑头基。使用表面压-平均分子面积（pi-mmA）测量法研究了具有 12（DoT-C12）、14（MyT-C14）、16（PaT-C16）和 18（StT-C18）个碳原子的 n-烷基链的 ATs 在空气-水界面上的 Langmuir 等温线。PaT-C16 和 StT-C-18 的 Langmuir 等温线的特征是在大约 20A(2)的 mmA 值处表面压的急剧增加，标志着 ATs 从已经垂直于水面取向的 n-烷基链的气态状态向凝聚态的转变。单层的崩塌发生在 20 到 36mNm(-1)之间，MyT-C14、PaT-C16 和 StT-C18 的等温线出现典型的“尖峰”，这可以归因于单层的弯曲和随后的折叠。崩塌点后，所有从 C12 到 C18 的 ATs 的表面压力出现略微增加的伪平台区域，表明 MyT-C14、PaT-C16 和 StT-C18 通过滚翻机制形成三层结构。进一步压缩时，最终在 59 到 67mNm(-1)之间的 pi 值发生崩塌。从可逆性研究中发现，ATs 的 Langmuir 等温线是不可逆的。通过原子力显微镜研究了 ATs 的 Langmuir-Blodgett 薄膜转移到硅片上的形态。
