adhesion

Pectin’s unique physicochemical properties have been linked to a variety of reparative and regenerative processes in nature. To investigate the effect of water on pectin repair, we used a 5 mm stainless-steel uniaxial load to fracture glass phase pectin films. The fractured gel phase films were placed on a 1.5–1.8 mm thick layer of water and incubated for 8 h at room temperature and ambient humidity. There was no immersion or agitation. The repaired pectin film was subsequently assessed for its optical and mechanical properties.

https://twitter.com/stephanebordas/status/1368289311523827714 The University of Luxembourg (UL) invites applications for two PhD Fellow (Doctoral Candidate) positions (m/f) as part of the QuaC project funded by the FNR CORE funding instrument https://www.fnr.lu/funding-instruments/core/

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*

M. Ciavarella (2021) Improved Muller approximate solution of the pull-off of a sphere from a viscoelastic substrate, Journal of Adhesion Science and Technology, DOI: 10.1080/01694243.2021.1882766

See also in attach the PDF.

dear collegues 

Static friction at fractal interfaces

https://doi.org/10.1016/j.triboint.2015.09.016

Just submitted a paper on electroadhesion of rough surfaces, greatly simplifying the recent theory of the great Bo Persson , with hot application to touch screens :  see here. 

Comments welcome.

The School of Engineering and Applied Science at the University of Pennsylvania invites applications for two full-time Postdoctoral Researcher positions in the laboratories of Prof. D.S. Srolovitz (https://www.seas.upenn.edu/directory/profile.php?ID=180) and Prof. Robert W. Carpick (http://carpick.seas.upenn.edu).

I attach a Letter I sent to the Editor of a tribology journal, concerning adhesion of rough surfaces. 

I contend that some "criteria" that have been proposed based on extrapolation of numerical results are due to the limitations in present numerical sophisticated rough contact simulations, which only span at most 3 orders of magnitude of wavelengths, so typically people simulate from nanometer to micrometer scale.