Stable But Conflicted Interfaces

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With this award, the Macromolecular, Supramolecular and Nanochemistry (MSN) Program is funding T. Randall Lee of the University of Houston for research to develop new and better materials that will find use in technologies ranging from medical implants to corrosion-resistant films. The approach involves the fabrication of films composed of dissimilar chemical species, such as oil and water that would not normally mix. When these films are applied to a surface, the result is a "conflicted" interface, where one part of an adsorbing molecule the oil-like part, for example may stick, while the other part will be repelled. Since unwanted or undesirable substances are less likely to adhere to these types of mixed surfaces, they have certain advantages. They are especially valuable for producing medical implants since they are more biologically inert than other surfaces. They are also more resistant to corrosion, opening up new realms of application for these materials. The work is having a broader impact on the development of new materials for a variety of technologies including the possible development of smart surfaces that will be capable of detecting trace chemical hazards. It is having a further broad impact on the training of a diverse future generation of scientists through the investigators' participation in several educational and outreach programs, including the University of Houston Latino Outreach program and others.In this research, the investigators are conducting a systematic exploration of organic thin films composed of chemical species that would normally phase separate in order to prepare ultrathin paint-like coatings that do no not exist in nature. The research focuses on three systems of current technological interest: (1) the design and development of multidentate adsorbates for stable thin-film coatings that contain a specified mixture of functional groups, either chemically similar or chemically dissimilar, to generate heterogeneous interfaces with unique composition and function; (2) the preparation of custom-tailored, partially-fluorinated adsorbate molecules to generate nanoscale fluorinated films having well-defined composition and structure, with the goal to define the critical elements needed to construct organic interfaces with controlled hydrophobicity, anti-adhesiveness, and lubricity; and (3) the investigation of thin-film architectures that mimic the backbones of industrially relevant polymers, with the goal to evaluate the properties and reactivity of ideal polymer surfaces. The research and education program has four main thrusts: (1) design and synthesis of new molecules to assemble structurally and chemically well-defined interfaces; (2) detailed characterization of the corresponding films; (3) thorough examination of interfacial wetting, adhesion and friction in these systems; and (4) integration of the major research concepts of organic chemistry, molecular self-assembly and nanotechnology into course modules for use in minority participation projects at the University of Houston.