Study On The Influence Of Different Washing Methods On The Surface Properties Of Gold And The Formation Of Self Assembled Monolayers

Self-assembled monolayers (SAMs) is referreds to a kind of monomolecular layer with some special structure and capability formed on a certain surface owing to the interaction of covalent bond or non-covalent bond between molecules and the substrate surface. Due to the ability to be endowed with special photoelectronic or catalytical property, etc., self assembled monolayers haves attracted great attention for the research on the application fields such as molecular devices, chemically modified electrodes, electrochemical conductivity, biosensor, optics transducer, energy transformer as well as high capability batteries. The structures of SAMs are determined and balanced by the correlated interaction of all factors including the surface characters, linkage forms between the adsorbed molecules and the substrate surface, the molecular structure and spatial effect, etc.Up to know, many methods including oxygen plasma treatment, UV/O3 treatment, piranha cleaning, etc, have been applied to clean various substrate surfaces for the formation of self assembled monolayers. However, as to our knowledge, there is no systematic investigation on the influence of different cleaning methods on the quality of formed self assembled monolayers.In this thesis, we choose oxygen plasma cleaning to clean gold surface for the formation of self assembled monolayers with terminal alkyl, hydroxyl, carboxylic group ,and compared it with results from the cleaning procedures with Piranha cleaning and UV/O₃ cleaning. By use of contact angle measurements and surface energy measurements, the compactness and unity can be characterized, which provide further information to explore the influence of different cleaning methods on the formation of self assembled monolayers on gold substrates.The main content of this thesis is focused on the following:1. Static contact angle measurement and analysis were performed on gold surface treated with different cleaning methods, which gave out the result that oxygen plasma cleaning could produce gold surface with the lowest contact angle. It meant that oxygen plasma cleaning could yield the best cleaning effect.2. Comparing the results of dynamic contact angle measurements and surface energy measurements, the effects of the three cleaning methods-oxygen plasma cleaning, Piranha solution cleaning, and UV/O₃ treatment were demonstrated, and oxygen plasma cleaning was recommended for gold surface cleaning procedure.3. The leaning effects were further demonstrated by the formation of self assembled...