Inspired by the ability of cacti to sop up as much water available, scientists from Pohang University of Science, South Korea, created a new material that could be beneficial for cosmetics, medical devices and other commonly used products. The cactus root-inspired material has the ability to rapidly absorb and retain water while minimizing the amount that is evaporated without changing other physical properties.
Cacti have a shallow, but extensive root system that allows the desert plant to soak up precipitation during rare desert rainfalls that seldom penetrate more than a few inches into the soil. The roots also dehydrate and shrink during droughts, creating air gaps that prevent water from escaping back into the soil.
To imitate the root system and the cacti’s outer covering, the researchers formulated a material composed of cellulose fibers, agarose cyrogel and microparticles. A cylindrical-shaped gel was developed and freeze-dried to form a structure that is similar to the layered composition of the cactus root epidermis.
Laboratory tests confirmed that the cactus root-inspired material is capable of absorbing water nearly 930 times faster than it loses it through evaporation. Experiments showed that 82 percent of the total water absorption capacity was recovered within one minute, while only 17 percent of the length extension occurred.
The mixture of components can be adjusted for specific applications. Inclusion of water-repellant microparticles could yield a material useful in oil separation and other oil-based engineering processes.