gels

Check out our new work at Advanced Materials Technologies

Simuli-responsive hydrogels that swell under constraints such as spatial geometric confinement are commonly employed in many applications to perform mechanical work. In this contribution, we present a simple 3D-printing based method to quantify the mechanical interactions between the gels and their environment. Our findings underscore the potential of gels in the design of actuators, sensors, biomedical devices, etc…

Please join us next week for a free virtual symposium on mechanics of gels. Click the link below for the symposium program and the Zoom links to all 12 sessions.

https://sites.utexas.edu/iutam2021/program/

Dear fellow iMechanicians,

Here is our recent paper published in EML on novel anti-icing materials based on propylene-glycol (PG) gels. This work was performed in collaboration with Xi Yao, Baohong Chen and myself while working in Zhigang Suo's lab at Harvard, and provides new solutions for anti-icing purposes (i.e. throug blankets design) without large and costly release of PG in the environment.

Anti-icing propylene glycol materials

Xi Yao, Baohong Chen, Xavier P. Morelle and Zhigang Suo*

Our recent work introduces a microscopically motivated model for the swelling response of polymer networks with non-covalent cross-linking bonds.

As opposed to the classical theories of rubber, we show that the uptake of water in polymer networks comprising hydrogen cross-linking bonds can lead to the dissociation of cross-links. This phenomenon leads to a reduction in the chain-density, an increase in entropy, and a decrease in the free energy.  As a result, the network experiences significant softening and exhibits a different mechanical response.

Jianyu Li, Yuhang Hu, Joost J. Vlassak, Zhigang Suo. Experimental determination of equations of state for ideal elastomeric gels. Soft Matter. publihsed online.

Due to the migration of mobile molecules and ions, a thin diffusive layer of distributed charge - the electric double layer - forms at the interface between a polyelectrolyte gel and a liquid ionic solution.  When two polyelectrolyte gels are brought closely together, the electric double layers overlap and interact with each other, resulting in an effective repulsion.  The multiphysics coupling nature of soft gels makes their surface interactions significantly different from the interactions between rigid solids.

Fascinating paper. Congrats to Wei, Xuanhe, and Zhigang. Nice to see a simple and an elegant model together with an intuitively appealing physical interpretation of the bifurcation phenomenon in gels. It woud be interesting to see the time evolution of the drying process and the orientation (theta) of the nano wires.