High Performance Materials
Ejima Laboratory

Bioinspired Polymers for Sustainable Environment and Advanced Medicine

Since ancient times, humankind has learned, imitated, and benefited from nature and living organisms. In recent years, the advancement of nanotechnology and molecular biology has significantly deepened our understanding of living organisms at the nano and molecular levels. As a result, bioinspired materials science is entering a new phase. Our research focuses on the design, synthesis, and engineering of polymeric materials, learning from how nature makes functional materials evolved over millions of years. Our long-term research goal is to "create our own materials" by converting the molecular design principles developed by nature to synthetic systems and contributing to the advancement of science and technology. In the short-term, we are conducting research projects on bioinspired materials such as, self-healing polymers, underwater adhesives, and the metal-phenolic networks (MPNs) coatings of biointerfaces.

Self-Healing Polymers in Wet Environments

Polymers are widely used in marine environments due to their lightweight nature, good processability, and unique thermal/mechanical properties. Crack formation and other types of damage in polymeric materials used in wet environments could eventually lead to wholescale failure and/or the spread of microplastic pieces into marine environments. Imparting self-healing capabilities to those polymers would be a beneficial strategy for extending the life time and reducing the maintenance cost. We are designing and synthesizing self-healing polymers that can self-heal in seawater through dynamic bondings such as hydrogen bondings and coordination interactions. A judicious design principle at multiple length scales is needed, as most of the existing self-healing polymers suffer from swelling-induced mechanical instability and loss of self-healing ability because of a severe water uptake in fully submerged conditions.

Bioinspired underwater adhesives

Putting a Band-Aid on wet skin is a challenging task because a thin water layer prevents the adhesion. Some marine creatures can produce biological molecules which are remarkably sticky even to wet surfaces. This inspired us to synthesize novel underwater adhesives, which we aim to apply for tissue repair, wound dressing and biomedical devices.

Interface Engineering using Metal-Phenolic Networks (MPNs)

Polyphenols are naturally occurring plant-derived chemicals. Polyphenolic molecules such as tannic acid show universal adherent properties. By adding metal ions as cross-linkers, metal-phenolic network (MPN) films are assembled in a surface-confined manner. The physicochemical properties of MPN-based materials depend on the polyphenolic molecules and metal ions used. MPNs are now regarded as a versatile coating platform and widely used all over the world to engineer nanomaterials and biointerfaces.

Member

• 
• • Professor
    Hirotaka EJIMA
  Research Area: Polymeric materials and biomimetics

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