Research Topics
Creation of novel functional materials by controlling intermolecular interactions
A mixture is a compound made up of several components, which can exhibit functions, structures, and reactions not possible by the individual substances. Our laboratory focuses on creating novel functional materials by controlling the aggregation and disaggregation of compounds in mixtures. We aim to discover new materials and phenomena related to “complex systems” by leveraging our expertise in organic, polymer, physical, and theoretical/informatics chemistry.
- Development of Soft Materials Using Lipophilic Electrolytes
- Post-modification of Metal-Organic Frameworks (MOFs) using Click Chemistry
- Development of composite materials using anisotropic surfaces of organic crystals
- Synthesis and function of polymer gels using Metal-Organic Frameworks as templates
- Molecular Design of LCST-type Phase Transitions in Polymer Solutions
Development of Soft Materials Using Lipophilic Electrolytes
Previous studies on polyelectrolytes primarily focused on highly polar solvents like water, with no known polyelectrolytes functioning in nonpolar environments (dielectric constant ε < 10). This limitation arises from ion aggregation in low dielectric conditions. To address this, we proposed developing a new “lipophilic polyelectrolyte” that retains functionality in nonpolar environments by incorporating ion pairs into the polymer chain that can dissociate in such conditions. Our research involves designing these lipophilic polyelectrolytes and exploring their potential applications.
- ACS Macro Letters 2012, 1(11), 1270-1273. link
As an example of applied development, we have developed a highly absorbent organic solvent resin that absorbs several hundred times its weight in organic solvents by cross-linking lipophilic polyelectrolytes. This material is expected to be a powerful tool for dealing with environmental issues such as recovering volatile organic compounds (VOCs), discharged oil, and oil fences.
We have demonstrated that the lipophilic polyelectrolyte gel we created undergoes discontinuous volume changes in response to slight changes in the solvent composition.
- Soft Matter 2008, 4, 748-750. (Hot Article) link
Post-modification of Metal-Organic Frameworks (MOFs) using Click Chemistry
Metal-organic frameworks (MOFs) are organic porous materials with various organic ligands and metal ions. The structure and coordination mode of the ligands can be freely designed, and the functions of organic porous materials can be directly reflected in the pores. Therefore, we have proposed a post-modification reaction in which the desired functional groups and structures are introduced using click chemistry after forming MOFs with azide groups in the organic ligands, and we are conducting research on this method.
- J. Am. Chem. Soc. 2008, 130, 14354-14355. link
Development of composite materials using anisotropic surfaces of organic crystals
Since the concept of crystal engineering, which involves designing the structure, properties, reactions, and functions of solids by designing their crystal structure, has been proposed, various single crystals of organic molecules have been reported. Since single crystals of organic molecules have characteristics that inorganic materials do not have, such as anisotropy and surface-specific morphology, they are expected to be used as functional materials. We are researching the construction of new molecular assemblies that actively utilize the specific properties and intermolecular interactions of organic crystals and apply them to solid materials by incorporating the concept of supramolecular chemistry.
Synthesis and function of polymer gels using Metal-Organic Frameworks as templates
By using the nano-pores of MOFs and cross-linking the organic ligands with a cross-linking agent from the outside, it was found that it is possible to convert a single crystal into a polymer gel. Both MOFs and polymer gels are structures with three-dimensional mesh structures. Still, no materials have seamlessly fused the two together until now. In addition, by controlling the shape and size of MOF crystals, we have also succeeded in preventing those of polymer gels. This means that we can design and synthesize polymer gels with polyhedral structures ranging from nano to micro sizes, and we can expect to see new developments in materials.
- Angew. Chem. Int. Ed. 2012, 51, 10566-10569. link
Molecular Design of LCST-type Phase Transitions in Polymer Solutions
Thermo-responsive polymers are attracting attention as stimuli-responsive materials. Among these, the LCST type phase transition, in which the conformation of the polymer changes when the temperature is increased, causing a sudden decrease in solubility, has not been studied much outside of the amphiphilic polymer (e.g., NIPAM) - water system due to the difficulty of molecular design. We have clarified the molecular design of polymers that cause LCST-type phase separation by introducing an effector that partially breaks the interaction between the functional groups of relatively soft polymer chains and creates a three-component system of solvent-polymer-effector. We expect it will be possible to construct new materials that can express LCST by skillfully utilizing intermolecular interactions in various media and temperatures.