Dry-Adhesives for soft interfaces

Adhesion is a common phenomenon that lie in the vicinity of the contact and advantages humans and several animals in their daily life [1]. Conventional pressure sensitive adhesives like sticky notes, adhesion of Galium-aparine seeds to the fabrics, adhesion of gecko on vertical wall and adhesion from tree frog on wet interfaces are few examples [2].

In recent years, gecko-inspired adhesives emerged as a promising alternative, establishing a new class of pressure sensitive adhesives that are dry, reusable, and residue-free. However, the current gecko-inspired structures are unable to adhere strongly to rough counter surfaces having micro-macroscopic surface roughness. Soft patterned surfaces having 3D microfeatures on it could be a solution, where the adhesion is based on mechanical interlocking of the features into the asperities of the counter surfaces.

Figure 1. Patterned  interfaces found in nature:  (a) Image of a  Gecko  along  with  SEM  pictures of its toe showing micro andnanometric pattern, (b) Galium aparine seeds with micrometric hooks responsible for mechanical interlocking, (c) a picture of3D printed pattern with mushroom features on it and (d) adhesion on a stretchable textile fabric of the moulded mushroom pattern in soft polymer.
Figure 1. Patterned interfaces found in nature: (a) Image of a Gecko along with SEM pictures of its toe showing micro andnanometric pattern, (b) Galium aparine seeds with micrometric hooks responsible for mechanical interlocking, (c) a picture of3D printed pattern with mushroom features on it and (d) adhesion on a stretchable textile fabric of the moulded mushroom pattern in soft polymer.

Aim

In this project, you will be using 3D printers and soft lithography techniques in order to develop the new class of dry adhesives that will be tested on unstructured rough counter surfaces for their adhesion and friction properties. A deep analysis and visual inspection of attachment-detachment process will help you to understand the underlying mechanism, which will be the basis for further improvements in the design of the surfaces. Knowledge of Matlab will be a plus for the project.

Methods/Techniques to be used

  • 3D printers, soft-lithography
  • Microscope
  • Adhesion meter, rheometer

This thesis proposal is an opportunity for a student to work on an existing research project going on in our lab and contribute significantly with possible outcomes in scientific community. Do not hesitate to contact if you want to know more about the project.

Contact person

Please write to Preeti Sharma or Joshua Dijksman for further questions.

References:

[1] Stanislav N Gorb. Biological attachment devices: exploring nature’s diversity for biomimetics. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 366(1870):1557–1574, 2008.

[2] Andrew J. Bowling, H. Brian Maxwell, and Kevin C. Vaughn. Unusual trichome structure and composition in mericarps of catchweed bedstraw (galium aparine).Protoplasma,233(3):223–230, Nov 2008