磷酯酰乙醇胺与硬脂酸和十八醇二元混合体系单层膜的热力学特性和AFM观测

高等学校化学学报 ›› 2010, Vol. 31 ›› Issue (3): 559.

磷酯酰乙醇胺与硬脂酸和十八醇二元混合体系单层膜的热力学特性和AFM观测

常怡光, 孙润广, 郝长春

陕西师范大学物理学与信息技术学院生物物理与生物医学工程研究室, 西安 710062

收稿日期:2009-06-26 出版日期:2010-03-10 发布日期:2010-03-10
通讯作者: 孙润广, 男, 教授, 博士生导师, 主要从事生物物理与生物医学工程研究. E-mail: sunrunguang@snnu.edu.cn
基金资助:
国家自然科学基金(批准号: 20772077)和教育部高等学校博士学科点专项科研基金(批准号: 200807180001)资助.

Thermodynamic Characteristics and Direct AFM Observation of Binary Mixtures of PE with Stearic Acid and Octadecanol

CHANG Yi-Guang, SUN Run-Guang*, HAO Chang-Chun

Laboratory of Biophysics and Biomedical Engineering, College of Physics and Information Technology, Shaanxi Normal University, Xi′an 710062, China

Received:2009-06-26 Online:2010-03-10 Published:2010-03-10
Contact: SUN Run-Guang. E-mail: sunrunguang@snnu.edu.cn
Supported by:
国家自然科学基金(批准号: 20772077)和教育部高等学校博士学科点专项科研基金(批准号: 200807180001)资助.

摘要/Abstract

摘要：

利用表面压力-平均分子面积(π-A)曲线的关系, 分别研究了在水/空气界面上形成的磷酯酰乙醇胺(PE)与硬脂酸(SA)和十八醇(OD)二元混合体系的热力学特性. 根据对弹性模量(C_S^-1)、过量分子面积(A_ex)以及表面过量吉布斯自由能(ΔG_ex)等热力学参数的数据计算, 定量分析了混合单层膜分子之间的相互作用. 实验结果表明, PE/SA和PE/OD单层膜两种组分之间摩尔比对其热力学参数有影响. 热力学分析表明, 在X_SA=0.2, 0.8和X_OD=0.8处, PE/SA和PE/OD二元混合体系的热力学参数[过量分子面积(A_ex)和表面过量吉布斯自由能(ΔGex)]相对理想状态均表现为负偏差作用, 说明分子之间的作用为引力作用. 相反, PE/OD二元体系在X_OD=0.2, 0.4, 0.6处, 表现为正偏差作用, 这说明分子之间的作用为斥力作用. AFM观测为PE/SA和PE/OD单层膜热力学特性的理论分析提供了有力的支持.

关键词: 磷酯酰乙醇胺; 单层膜; 弹性模量; 过量吉布斯自由能; 原子力显微镜

Abstract:

Thermodynamic characteristics of binary mixtures of phosphatidylethanolamine(PE) with stearic acid(SA), and octadecanol(OD) formed at the air/water were investigated in terms of surface pressure(π)-area(A) relation. On the basis of the data, the thermodynamic parameters of compression modulus(C_S^-1), excess mean area per molecule(A_ex), and surface excess Gibbs energy(ΔG_ex) were calculated. We can quantitatively analyze the molecular interactions in the mixed monolayers. The experimental results showed that the various molar ratios of the two components, PE and SA, PE and OD, influenced thermodynamic parameters. The thermodynamic analysis indicated that the thermodynamic parameters[excess molecular area(A_ex), surface excess Gibbs energy(ΔG_ex)] of PE/SA and PE/OD were obtained maximum negative deviation from the ideal behavior at X_SA=0.2, 0.8 and X_OD=0.2, suggesting an attractive interaction between molecules. The other way round, the molar ratios of OD at X_OD=0.2, 0.4, 0.6, were found to be conspicuously maximum positive, suggesting an intermolecular repulsion. The AFM images of mixed PE/SA and PE/OD monolayers are in favor of the theoretic analysis of the thermodynamic characteristics.

Key words: Phosphatidylethanolamine; Monolayer; Compression modulus; Excess Gibbs energy; Atomic force microscopy

TrendMD:

常怡光, 孙润广, 郝长春. 磷酯酰乙醇胺与硬脂酸和十八醇二元混合体系单层膜的热力学特性和AFM观测. 高等学校化学学报, 2010, 31(3): 559.

CHANG Yi-Guang, SUN Run-Guang*, HAO Chang-Chun. Thermodynamic Characteristics and Direct AFM Observation of Binary Mixtures of PE with Stearic Acid and Octadecanol. Chem. J. Chinese Universities, 2010, 31(3): 559.

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