Keywords: self–assembled monolayers, aminopropyltrimethoxysilane, APTMS, fullerene C60, silicon oxide, grafting kinetics, silicon dioxide, surface functionalisation, ordering kinetics, nanotechnology
Dry and wet methods of silicon dioxide surface functionalisation with 3–aminopropyl trimethoxysilane: application to fullerene C60 anchoring
In this work, we have studied the formation of self–assembled monolayers (SAM) of 3–aminopropyltrimethoxysilane (APTMS), chemically bound to silicon dioxide surface, prepared using a deposition from both solution and a new solvent–free process, using contact angle measurements, ellipsometry, ATR–FTIR spectroscopy and AFM imaging. In the first part, we have analysed the grafting kinetics of APTMS SAMs to control the formation of a single monolayer. Results show that with the dry deposition method about 4 h are needed to obtain a complete APTMS single monolayer. In parallel, the ordering kinetics of the SAM has been monitored by ATR–FTIR spectroscopy, showing that the monolayer reaches its final order before grafting. The possibility of using the as–obtained APTMS SAMs from wet and dry methods for anchoring functional molecular moieties is then probed with fullerene C
60molecules deposited from a solution. The grafting kinetics of C
60is studied on wetly deposited APTMS, showing a first step at about two monolayers. At last, comparative analysis of C60 grafted on either dryly or wetly deposited APTMS shows that the latter allows obtaining more homogeneous C
60layer. Such results could help in paving the way to the preparation of hybrid C
60–based molecular devices on silicon through a bottom–up approach.