Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.12: Poster

Tuesday, March 8, 2005, 16:30–18:30, Poster TU D

A Novel Method for Determining Thickness of Self-Assembled Monolayers — •Saju Pillai, Sabine Hild, and Othmar Marti — Department of Experimental Physics, University of Ulm, Ulm, Germany, D-89069

Usually, thickness of a completely formed monolayer has been achieved using Ellipsometry as the silanes are covalently bonded to the substrate through Si-O-Si bond. However we could develop an easy and convenient method to determine the thickness of a completely formed monolayer by employing a ’selective dissolution’ method combined with atomic force microscope(AFM). Especially we studied monolayer formation and growth mechanism of octadecylsiloxane obtained using octadecyltrimethoxysilane(OTMS). OTMS exhibits a monolayer growth through an island expansion process similar to octadecyltrichlorosilane, but with a slow growth rate. The average height of islands, surface coverage, contact angle and RMS roughness increase with OTMS adsorption time in a consecutive manner. The ’selective dissolution’ method was extended to determine the monolayer thickness of various silanes with different C-chain lengths. The samples were analyzed and characterized in both Pulsed Force Mode and Tappingmode in a custom built and commercially available AFMs.