Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.

(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)

Materials assembly using molecular recognition and redox -modulated recognition

Joseph B Carroll, University of Massachusetts Amherst


The integration of non-covalent interactions in materials provides a direct mechanism to customize materials properties to specific applications and create novel nanostructures. Combining self-assembly with non-covalent interactions serves as a powerful tool in the creation of complex macromolecular structures with thermodynamically reversible contacts. With a host of non-covalent interactions available (e.g. dative bonding, hydrogen bonding, electrostatic pairings, π-stacking), tailoring the size and stability of self-assembled materials can be achieved through choice of interaction. This thesis describes two distinctive areas of research employing a rational combination of self-assembly and non-covalent interactions: (1) the synthesis and self-assembly of recognition unit functionalized Polyhedral Oligomeric Silsesquioxane (POSS) units and (2) the study of redox-modulated, molecular recognition in macromolecular systems. POSS units have long been employed as covalent additives in both polymeric and ceramic-based systems. Now, they have found alternative uses as non-covalent modifiers in multiple supramolecular systems. POSS units inherently feature a variety of attributes, which make them attractive as molecular recognition elements. These three-dimensional, nanoscale "building blocks" (∼0.6 nm inner silicate core) can easily be functionalized with a variety of recognition units. Through synthetic modification we were able to create a versatile component for non-covalent self-assembly with defined spacial orientations. To that end, recognition unit functionalized POSS units have been shown to serve as potent non-covalent modifiers for applications including surface modification, nanoparticle self-assembly, thermal enhancement in polymeric systems, and potential cellular delivery systems. Modulating non-covalent interactions via the reduction or oxidation of a molecule serves as an effective means in tuning the formation of supramolecular assemblies. Initial solution-based studies of both non-specific (urea-quinone) and specific, three-point (flavin-diamidopyridine) hydrogen bonding systems have been successful in understanding the complex behaviors, which govern redox-modulated molecular recognition. This understanding led to the incorporation of electrochemically tunable "host-guest" interactions on polymers and surfaces. Several interesting behaviors ranging from reversible redox-modulated recognition to induced proton transfer processes were observed and the ongoing focus of this research seeks to combine materials applications and redox-modulated recognition to create responsive, electrochemically tunable polymers and surfaces.

Subject Area

Organic chemistry|Materials science

Recommended Citation

Carroll, Joseph B, "Materials assembly using molecular recognition and redox -modulated recognition" (2005). Doctoral Dissertations Available from Proquest. AAI3193888.