The Rudick lab is interested in strategies to minimize or even eliminate heterogeneity in multifunctional materials. Heterogeneity in multifunctional polymers and nanoparticles complicates the interpretation of structure-property relationships and can lead to batch-to-batch variability in properties. Several types of heterogeneity arise in polymers made up from different functional monomers including: (i) chain length (or molecular weight) dispersity, (ii) non-uniformity of monomer sequence, and (iii) differences in the ratio of monomers incorporated in each polymer molecule. Existing analytical tools are insufficient to characterize these complex mixtures, so we are exploring synthetic and supramolecular chemistry approaches to tame the complexity of multifunctional materials. Strategies for controlling either the ratio or arrangement of the monomers can yield materials with highly tailored properties or properties that are unique from those of heterogeneous polymer materials.
Multicomponent Reactions as Methods for Controlled Multifunctionalization
Multicomponent reactions combine three different reactants into a single product, which is advantageous for the synthesis of multifunctional materials. We have shown that the Passerini three-component reaction can be used to control the ratio of functional subunits in three-arm star-branched liquid crystals (Org. Lett. 2015) as well as in dendritic polymers (Org. Lett. 2012; Chem. Commun. 2015). Additionally, multicomponent reactions offer advantages such as efficiency and versatility. We are exploiting the advantages of multicomponent reactions to explore properties that are unique to these well-defined multifunctional materials.
Synthesis of three-arm star mesogens via multicomponent reactions.
Self-Assembly and Self-Organization of Peptide-Dendron Hybrids
Iterative synthesis methods have enabled the synthesis of monodisperse and sequence-defined macromolecules such as peptides and dendrimers. Combining the diverse physical properties that are available to different dendrimers with the folding and self-assembly behaviors of peptides yields hybrid biomaterials whose properties can be tailored with exceptional precision. We have developed a convenient and bioorthogonal approach grafting dendrons to peptides (Biopolymers 2015). We have shown that protein design principles can be applied to the design of peptide-dendron hybrids that self-assemble into dendronized helix bundle motifs (Chem. Commun. 2015; Biomacromolecules 2016).
Folding and assembly of a peptide-dendron hybrid into a dendronized helix bundle.