First step in the design and realisation of a 'smart' switchable surface

Abstract

This thesis reports the first step in the design and fabrication of a double armed switchable surface that exhibits dynamic changes in its interfacial properties in terms of bio-recognition, in response to an electrical potential (Figure 1a). The aim of the work herein is to develop a suitable synthetic strategy to ensure the stability of the desired self-assembled monolayer (Figure 1b). In order to obtain a better understanding of the possible chemical interactions involved, different portions of the surface have been studied separately on a simpler system (Figure 1c). Figure 1 a) Cartoon image showing the opening of the positively charged double armed system when a negative voltage is applied and consequent interaction between biotin and streptavidin, b) chemical structure of the double armed switchable surface, c) scheme and chemical structure of the selected portions examined in the present research. In particular, this thesis will discuss the successful coupling of biotin (Figure 1c) with a 4-hydroxybenzaldehyde derivative and the attempts to obtain a ‘double armed’ 3,5-dihydroxybenzaldehyde derivative (Figure 1c) via a Huisgen reaction. The last section of this work will focus on the fabrication and characterisation of pure and mixed aromatic monolayers of 4-aminothiophenol and 4-methylbenzenethiol