Water-Borne Self-Assembled Monolayers and Films

Vanderbilt University, Nashville TN

Investigators

Abstract

ABSTRACT CTS-9983966 Jennings - Vanderbilt U. This proposal seeks to develop new methodologies for forming self-assembled monolayers (SAMS) that will expand the uses and applications of these molecular films. The approach utilizes the assembly of alkanethiolate SAMs onto metal supports from aqueous solutions instead of the traditional organic solvents. The proposed work exploits the molecular design of water-soluble adsorbates and the control of aqueous processing variables including pH, electrochemically benign aqueous solvents. The information of the SAMs can be monitored in situ by electrochemical techniques such as interfacial capacitance measurements. The proposed work will also investigate the feasibility of using water-borne SAMs in applications. Through the hydrophobic effect, the low-energy surfaces formed from aqueous solvents will serve templates for the formation of surfactant films or layered, self assembling systems that can be removed from the substrate and used as ultrathin skins for membrane separations. The proposed research also provides new opportunities for applying SAMs to alleviate engineering problems such as corrosion. Water-borne SAMs will be used as aqueous-phase corrosion inhibitors to provide and maintain a ultrathin barrier layer that impedes the transport of aqueous species to an underlying metal such as copper or iron in continuous contact with an aqueous phase. The advantages of forming self-assembled monolayers in aqueous solutions include (1) environmentally clean processing of films and coating, (2) the ability to utilize hydrophobic interactions to engineer novel self-assembled systems (3) the use of added surfactant, electrochemical potential, and pH to gain an unprecedented control over the molecular-level properties of SAMs, and (4) the development of new technological applications for SAMs in aqueous systems. The study of SAM formation in aqueous solution will likely spark the fusion of knowledge from two separate areas of colloid and surface chemistry involving research on micellar systems and that on self-assembled monolayers. This fusion should result in a dramatic increase in the generation of novel self-assembled systems with unique properties, superior stabilities, and attractive potential for applications.