TY - JOUR T1 - Growth kinetics and thermodynamic stability of octadecyltrichlorosilane self-assembled monolayer on Si (100) substrate JF - Materials Letters Y1 - 2005 A1 - Kulkarni, S. A. A1 - Mirji, S. A. A1 - Mandale, A. B. A1 - Gupta, R. P. A1 - Vijayamohanan, K. P. KW - Gibbs's free energy (AG) KW - growth kinetics KW - octadecyltrichlorosilane (OTS) KW - self-assembled monolayers (SAMs) KW - Zisman plot AB -

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.

PB - ELSEVIER SCIENCE BV CY - PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS VL - 59 IS - 29-30 U3 -

Foreign

U4 - 2.437 ER -