Paper Number
PO11 

Session
Poster Session

Title
Spiders tune glue viscosity to maximize adhesion

Presentation Date and Time
October 14, 2015 (Wednesday) 6:05

Track / Room
Poster Session / Atrium/Harborview

Authors (Click on name to view author profile)

1. Amarpuri, Gaurav (University of Akron, Polymer Science)
2. Zhang, Ci (University of Akron, Polymer Science)
3. Diaz, Candido (University of Akron, Integrated Bioscience)
4. Blackledge, Todd (University of Akron, Integrated Bioscience)
5. Opell, Brent (Virginia Tech, Department of Biological Science)
6. Dhiojwala, Ali (University of Akron, Polymer Science)

Author and Affiliation Lines (in printed abstract book)
Gaurav Amarpuri¹, Ci Zhang¹, Candido Diaz², Todd Blackledge², Brent Opell³, and Ali Dhiojwala^1
1Polymer Science, University of Akron, Cuyahoga Falls, OH 44221; ²Integrated Bioscience, University of Akron, Akron, OH; ³Department of Biological Science, Virginia Tech, Blacksburg, VA

Speaker / Presenter 
Amarpuri, Gaurav

Text of Abstract
Adhesion in humid conditions is a fundamental challenge to both natural and synthetic adhesives. Yet, glue from most spider species becomes stickier as humidity increases. We find the adhesion of spider glue, from five diverse spider species, maximizes at very different humidities, that matches their foraging habitats. By using high-speed imaging we find that the glue viscosity varies over five orders of magnitude with humidity for each species, yet the viscosity at maximal adhesion for each species is nearly identical, 10⁵-10⁶ cP. Many natural systems take advantage of viscosity to improve functional response, but spider glue's humidity responsiveness is a novel adaptation that makes the glue stickiest in each species' preferred habitat. This tuning is achieved by hygroscopic organic salts that determine water uptake in the glue. We therefore anticipate that manipulation of hygroscopic salts to control viscosity will provide a simple mechanism to design humidity responsive smart adhesives.