Ionic spiderwebs

Abstract

Spiders use adhesive, stretchable, and translucent webs to capture their prey. However, sustaining the capturing capability of these webs can be challenging because the webs inevitably invite contamination, thus reducing its adhesion force. To overcome these challenges, spiders have developed strategies of using webs to sense prey and clean contaminants. Here, we emulate the capturing strategies of a spider with a single pair of ionic threads based on electrostatics. Our ionic spiderwebs completed consecutive missions of cleaning contamination on itself, sensing approaching targets, capturing those targets, and releasing them. The ionic spiderwebs demonstrate the importance of learning from nature and push the boundaries of soft robotics in an attempt to combine mutually complementary functions into a single unit with a simple structure.

Hydrogel-based strong and fast actuators by electroosmotic turgor pressure

“…Because of their softness, transparency, biocompatibility, and responsiveness to stimuli, hydrogels are attractive candidates for soft actuators and have been applied in various fields such as soft robotics ( 1 , 2 ), tunable optics ( 3 ), fluidics ( 4 ), and biomedicine ( 5 ). The actuation mechanism of most hydrogel actuators is swelling, driven by osmotic pressure in response to external stimuli such as solvent ( 6 ), temperature ( 7 ), pH ( 8 ), electric field ( 9 ), and light ( 10 ).…”

Soft artificial electroreceptors for noncontact spatial perception

“…S5), the density of the object surface charge increased, and a higher voltage was induced across the external load. Meanwhile, although the electron affinity of glass and alumina are quite similar, perceptible values of 23 mV pp were still observed when the glass object was charged with alumina ( 21 ). This indicates that objects in the vicinity can be sensed using the SAER as long as they are charged.…”

“…Because contact with its surroundings causes the object to be charged through contact electrification, objects usually have static charges on their surfaces (Fig. 4A) (21,22,(30)(31)(32). When an object is approaching the receptor, electric fields originating from the object gradually increase the induced voltage in the hydrogel electric field receiver of the SAER (Fig.…”

Recent Progress of Spider-Silk-Inspired Adhesive Materials

“…Except for surface coating, surface polymerization has also been used to fabricate spider-silk-inspired adhesive materials. By polymerizing the precursor of organogel solution (acrylamide and LiCl in ethylene glycol) on the surface of plasma-treated silicone rubber, a multifunctional artificial ionic spider web was fabricated, displaying fascinating properties such as self-cleaning, sensoring, and adhesive properties . The mechanical property of this artificial spider web is similar to natural spider web, in which the extensibility and the stiffness of capture thread display values that are, respectively, 10 times higher and 3300 times lower than that of the framework thread.…”