Growth kinetics and thermodynamic stability of octadecyltrichlorosilane self-assembled monolayer on Si (100) substrate
Growth kinetics and thermodynamic stability of octadecyltrichlorosilane self-assembled monolayer on Si (100) substrate
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DOI：
10.1016/j.matlet.2005.07.026
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发表时间：
2005-12-01
影响因子：
3
通讯作者：
Vijayamohanan, KP
中科院分区：
文献类型：
--
作者：
Kulkarni, SA;Mirji, SA;Vijayamohanan, KP
研究了十八烷基三氯硅烷（OTS）自组装膜在Si（100）衬底上的生长动力学和热力学稳定性，以了解其在控制膜的粘附性和表面疏水性方面的作用。随时间变化的接触角测量，使用水作为OTS浓度的函数，显示在初始阶段快速单层形成，随后缓慢达到完全覆盖，并且总体动力学近似遵循Langmuir吸附等温线。发现吸附速率常数（k（a）= 150 M-1 s（-1））显著大于脱附速率常数（k（d）= 0.156 s（-1）），而吉布斯自由能（Δ G（ads））变化量为-4.2 kcal/mol，表明OTS单层在硅表面上的热力学稳定性。部分单层形成的“均匀”的生长机制，即使在低覆盖率，揭示了原子力显微镜（AFM）结合掠角FTIR光谱。使用Zisman图分析界面粘附性质表明，Si（100）表面上OTS单层的临界表面张力（γ（c））为20.7 dyn/cm。(C)2005 Elsevier B. V.保留所有权利。
We have studied the growth kinetics and thermodynamic stability of octadecyltrichlorosilane (OTS) self-assembled monolayers on Si (100) substrate in order to understand its role in controlling the adhesion and surface hydrophobicity. Time-dependent contact angle measurements, using water as a function of OTS concentration, show rapid monolayer formation in the initial stage followed by a slow attainment of full coverage and the overall kinetics approximately follows the Langmuir adsorption isotherm. The adsorption rate constant (k(a) = 150 M-1 s(-1)) is found to be significantly greater than the desorption rate constant (k(d) = 0.156 s(-1)) while the Gibbs free energy (Delta G(ads)) change amounts to -4.2 kcal/mol suggesting thermodynamic stability of OTS monolayer on a silicon surface. Partial monolayer formation by a 'uniform' growth mechanism, even at low coverage, is revealed by atomic force microscopy (AFM) in conjunction with grazing angle FTIR spectroscopy. Analysis of the interfacial adhesion properties using Zisman plot suggests a critical surface tension (gamma(c)) of 20.7 dyn/cm for OTS monolayer on Si (100) surface. (C) 2005 Elsevier B.V. All rights reserved.