Our team aims to create water-based materials, referred to as aqua materials, as replacements for conventional plastics. Taking advantage of their unique properties as moldable, portable water, together with the elaboration of their inner or surface parts, we will demonstrate their various applications as intelligent soft materials. We are employing a wide range of chemicals as the components of aqua materials, in order to improve their properties and to ultimately realize environment-conscious materials. Our challenge also includes the rational design of novel bio-inspired materials, by assembling molecules with dynamic and static functions within aqua materials used as scaffolds.
Synthetic hydrogel like cartilage, but with a simpler structure
– Potential as artificial cartilage and anti-vibration materials –
Electrostatic and magnetic repulsive forces are used in various places, as in maglev trains, vehicle suspensions or non-contact bearings etc. However, design of polymer materials, such as rubbers and plastics, has focused overwhelmingly on attractive interactions for their reinforcement, while little attention has been given to the utility of internal repulsive forces. Nevertheless, in nature, articular cartilage in animal joints utilizes an electrostatically repulsive force for insulating interfacial mechanical friction even under high compression.
We discovered that when nanosheets of unilamellar titanate, colloidally dispersed in an aqueous medium, are subjected to a strong magnetic field, they align cofacial to one another, where large and anisotropic electrostatic repulsion emerges between the nanosheets. This magneto-induced temporal structural ordering can be fixed by transforming the dispersion into a hydrogel. The anisotropic electrostatics thus embedded allows the hydrogel to show unprecedented mechanical properties, where the hydrogel easy deforms along a shear force applied parallel to the nanosheet plane but is highly resistive against a compressive force applied orthogonally.
The concept of embedding repulsive electrostatics in a composite material, inspired from articular cartilage, will open new possibilities for developing soft materials with unusual functions.
Hydrogel embedded with an anisotropic electrostatic repulsive force.
Photoreactions activate magnetic nanoswitches
