PRESS RELEASE

A Groundbreaking Lightweight Materials: Synthetic Luffa Sponge Created using Water and Electricity

Written by Public Relations Office | Jul 4, 2025 1:00:00 AM

As plastic waste continues to pose a serious global environmental issue, technologies that enable the creation of functional materials using minimal resources are gaining attention for the realization of a sustainable future. The research team has developed a new ultra-light and robust artificial sponge similar to the natural luffa. Like its natural counterpart, this material combines softness and strength—qualities that change depending on its water content—making it a highly versatile “smart material.”

What’s especially remarkable is how simple and eco-friendly the production process is. All it takes is water and a few common chemicals. By applying a low voltage for just two minutes, a nearly invisible membrane with a thickness of 70 nm forms uniformly on an electrode surface. When the voltage is turned off, the membrane naturally lifts off the electrode and floats to the surface.

The membrane is highly porous, with countless tiny pores. As a result, it is about half the density of ordinary plastics, yet has a mechanical stiffness 3–4 times greater than typical resins. Such a combination of lightness and strength has never been seen before in synthetic porous polymers—except in specially processed fibers.

Like natural luffa, the membrane becomes soft and swells in water, especially under alkaline conditions (high pH). This means the membrane can function as a smart membrane that automatically switches between open and closed states for tunable permeability based on pH—ideal for use in responsive filtration systems.

Additionally, the membrane’s antibacterial and antiviral properties open up exciting possibilities for use in protective filters. Even more, when the membrane is carbonized (heated without oxygen), it transforms into a large-area, defect-free, electrically conductive carbon membrane, while retaining its original shape and porous structure. This makes it a promising material for electrodes in energy storage devices, such as electric double-layer capacitors.

Because this technique uses only water and electricity, it minimizes resource use and environmental impact. The method is also suitable for continuous roll-to-roll production, marking it as an innovative technology that could drive the future of lightweight, high-strength functional materials.

 

 

Papers

Journal: Science

Title: Electric double-layer synthesis of a sponge-like, lightweight reticular membrane

Authors: Yoshimitsu Itoh*, Tengfei Fu, Pier-Luc Champagne, Yudai Yokoyama, Kunita Numabe, You-lee Hong, Yusuke Nishiyama, Hsiao-Fang Wang, Akemi Kumagai, Hiroshi Jinnai, Hirohmi Watanabe, Teiko Shibata-Seki, Asuteka Nagao, Tsutomu Suzuki, Yukie Saito, Keigo Wakabayashi, Takeharu Yoshii, Atsushi Izumi, Katsumi Hagita, Junichi Furukawa, and Takuzo Aida*

DOI: 10.1126/science.adq0782

 

 

UTokyoFOCUS | Press Release: https://www.u-tokyo.ac.jp/focus/en/press/z0508_00413.html