All adhesives in widespread use today can be considered “wet” adhesives. These materials are typically applied to a surface in a liquid state and achieve intimate contact by flowing along the surface and wetting surface asperities. To be an effective adhesive, the liquid must be transformed into a solid with high cohesive strength through either a chemical reaction (crosslinking), or in the case of hot melts, by cooling below the melting temperature.
Akron Ascent Innovations is the first company to use electrospinning to produce dry adhesives, which offers the potential for solvent-free, environmentally friendly adhesives that have a remarkable combination of strength and clean, damage-free removability not possible with conventional adhesive technologies.
AAI’s dry adhesive technology is based on the principle of contact splitting, which is a robust and reversible (elastic) mechanism of adhesion commonly exploited by animals such as flies, beetles, spiders, and the most prolific climber of all, the gecko. All surfaces have some attractive force between them arising from weak, inter-molecular forces known as van der Waals (vdW) forces. This force decreases linearly with the size of the contact, but the resulting stress (force divided by area), increases. As a result, a surface made up on a large number of small contact sites will have an immensely larger interaction with a target surface than a smooth one.