New Technology Of Applying Material "Electric Adhesion" To Join Fabrics

In the report published on ACS Applied Materials and Interfaces, researchers from the University of Maryland said that now there is a new method to "weld" viscous things together without glue. They demonstrated a universal "electro adhesion" technology, which can bond soft materials together by electricity.

Whether it is bonding plastic, fabric, wood or other materials, almost always there is a glue that can be used. But when the materials are soft, such as tissues or artificial organs, things will become a bit tricky. 3D printing and other strategies can fuse the whole structure (such as organs) together at one time without glue, but this process is slow and laborious, and requires advanced technology and equipment.

The other option is electric adhesion, that is to use an electric field to keep oppositely charged materials together to form a connection between the components of the material. The process may involve chemical bonds, such as ionic bonds, or more physical connections, such as winding polymer chains together, requiring only a household battery and pencil lead.

The team tested a gel and three capsules made from alginate or chitosan. Both capsules are naturally occurring polymers, either positively or negatively charged. When connected to the graphite electrode and exposed to a 10 volt electric field for about 10 seconds, the opposite charged materials stick together.

The research team used electro adhesion to form a solid structure of millimeter sized capsules in 3D, which is faster and easier than any alternative technology. This connection is strong enough to withstand gravity and may last for several years. In addition, by reversing the flow of electricity, this connection force can be "destroyed", thus eliminating and repairing any errors in the assembly process.

Electroadhesion can also be used for selective classification of charged soft materials. For example, a "finger robot" can selectively "pick up" capsules with opposite charges through electrical adhesion, and then "put down" these structures by reversing the polarity.

Overall, this study shows how to use an electric field to connect soft materials without the need for adhesives or glues. The researchers said that this proved the universality of electro adhesion, which may one day be used in robotics and tissue engineering.