slides

I gave a seminar at Xian Jiaotong University on 27 October 2009.  I recently found the video of the seminar online.  The seminar was in Chinese, but the slides were in English.

• Video of the seminar
• Slides of the seminar  

If the subject interests you, the following papers will lead you to the literature.

At the invitation of Yonggang Huang, I’ll give 4-hour lectures at the NSF Summer Institute Course on the Mechanics of Soft Materials.   I attach the slides of the lectures, to be given on Monday, 10 May 2010.  An abstract of the lectures follows.

I’ve just come back from a Winter School on Dielectric Elastomer Transducers, held at Monte Verità, Ascona, Switzerland, 10-16 January 2010.  Lectures were given by various people, covering the theory of electromechanical interaction, design of devices, development of materials, and technologies of manufacturing.  I was asked to give three lectures on the theory.  I attach the slides of my lectures.

Recent experiments have shown that a voltage can induce a large deformation in an elastomer of interpenetrating networks. We describe a model of interpenetrating networks of long and short chains. As the voltage ramps up, the elastomer may undergo a snap-through instability. The network with long chains fills the space and keeps elastomer compliant at small to modest deformation. The network with short chains acts as a safety net that restrains the elastomer from thinning down excessively, averting electrical breakdown.  It appears possible to find a dielectric elastomer capable of giant deformation of actuation.  You can read the paper, or take a look at the slides posted here.

In May 2008, I posted 3 lectures on Soft Active Materials given at UCSB.  I have since given similar lectures on other occasions, but never all three at the same place.  The field has been active.  The lectures have been updated with new items.  I’m now posting the “2nd edition” of these lectures.

• Dielectric elastomers
• Neutral gels
• Polyelectrolyte gels
• pH-sensitive gels 

The slides are posted as delivered.  No effort is made to eliminate repeating slides. 

The question was raised in class as to what the appropriate equilibrium condition for a column of fluid at rest should be. Specifically, given we expect a hydrostatic gradient in pressure with height, whether  the chemical potential must be the same throughout the column was questioned. Here are my first thoughts. In brief, I assert that  the chemical potential must be everywhere identical, and that the pv term is balanced, at every height in the column, by the potential energy conferred by position in a gravitational field.

At the invitation of David Clarke on behalf of the UCSB/Los Alamos Institute of Multiscale Materials and Structures, I gave the following three lectures:

1. Large deformation and instability in dielectric elastomers
2. Large deformation and instability in swelling polymeric gels
3. Mechanics and electrochemistry of polyelectrolyte gels

The abstracts follow, and the slides are attached at the end of this post.

Rob Wood teaches a course on micro/nano robotics, and asks me to give a 30-minute tutorial on the theory of dielectric elastomer actuators (DEAs).  I attach my slides, which might be useful to you if you'd like to include this topic in your class.  The tutorial draws upon work in the literature, as well as recent work in my group:

I'm attaching slides of a talk that I gave yesterday at the Schlumberger-Doll Research Center.  In preparing the talk, I made liberal use of slides prepared by Wei Hong for his own presentations.  The talk is mainly based on the following papers: