Multifunctional supramolecular materials

His research interest is focused on the synthesis and development of novel organic functional materials in the area of emerging technologies. This includes multifunctional polymers, molecular glasses, and supramolecular polymer additives and gelators. Combinatorial methods to efficiently synthesize and screen materials properties of polymer and supramolecular materials and functions of devices are an additional aspect. 

Physical cross-linking is easily incorporated into the structures of supramolecular side-chain polymers by using bi- or multifunctional molecules [9,31,93]. The complexation of the functionalized polyacrylates, a stilbazole, and bipyridine molecules form supramolecular side-chain cross-linked polymer 37 (Figure 27) [31,93]. Bis-imidazolyl compounds are also used for such cross-linking [105]. Reversible association-dissociation of the hydrogen bonding leads to the reversible thermal order-disorder transitions, which is an important feature of supramolecular materials. Liquid-crystalline main-chain supramolecular networks have been prepared from multifunctional components [32,123-126], which will be described in Section IV. 

The vast range of supramolecular polymeric materials also extends from the use of small molecules (e.g., double-sided discotics or multifunctional monomers with a discrete tether) to very large molecules (polymeric or dendritic). Another important characteristic of SPs is the timescale upon which the chains exist, which is defined by the rate of association/ dissociation of the monomers. Tme dynamic SPs must be reversible (breaking and recombining) on experimental time-scales (e.g., NMR timescale). A physical model developed by Cates and co-workers predias many viscoelastic properties of SPs as a funaion of the strength of the noncovalent interactions existing between monomers.Although initial studies focused on wormlike micelles, the model has been demonstrated to successfully describe the viscosity behavior of reversible, self-complementary UPy-based SPs. ... 

Xerox Corporation has filed two patents in which supramolecular polymers are used as binders in ink compositions. One application relates to hot-melt inks, consisting of a colorant and a binder [29]. These inks are solid at temperatures below 50°C, and liquid with a viscosity around 20 cps at 160 C. The binder is a multifunctional low molecular weight compound that has been functionalized with 2 to 5 UPy-groups, resulting in polyether compounds that form supramolecular networks. Mixing these materials at elevated temperatures with other ingredients like UV-stabilizers, antioxidants, and colorants, results in inks that can be used in hot-melt ink printers. 

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