There is an immediate opening of a postdoctoral researcher in the Mechanics of Soft Materials Lab (https://www.msm.seas.ucla.edu/) in the Department of Mechanical and Aerospace Engineering at the University of California, Los Angeles (UCLA). The research will be on experimental mechanics of soft materials, and fabrication of soft machines. The successful candidate should have a PhD degree with expertise in experimental polymer materials.
There is an immediate opening of a postdoctoral researcher in the Mechanics of Soft Materials Lab (https://www.msm.seas.ucla.edu/) in the Department of Mechanical and Aerospace Engineering at the University of California, Los Angeles. The research will be on experimental mechanics of soft materials, and fabrication of soft machines. The successful candidate should have a PhD degree with expertise in experimental polymer chemistry and polymer materials.
In this paper, we introduce a new simple yet effective strategy to form "hydrogel skins" on polymer-based medical devices with arbitrary shapes. Hydrogel skins can convert any surface of polymer devices into robust, wet, soft, slippery, antifouling, and ionically conductive without affecting the original properties and geometries.
It is my first blog entry to iMechanica after long period of only reading.
In this review published in Chemical Soceity Reviews, we systematically revealed the design principles for bioelectronics and discussed hydrogels' merits and potential in bioelectronics.
Nemo lives in the ocean near the Great Barrier Reef. One day, he bought a hydrogel balloon which is inflated by an inner pressure p. Will the balloon burst eventually or stay safe?
https://doi.org/10.1002/mabi.201800253In celebration of Stern Family Professor of Engineering David L. Kaplan, on the occasion of his 65th birthday, we review a selection of relevant contributions of computational modeling to understand the properties of natural silk, and to the design of silk-based materials, especially combined with experimental methods.
Here is our recent paper “Fatigue Fracture of Self-Recovery Hydrogels”. To the hydrogel community, this paper distinguishes the fatigue fracture and the self-recovery of a hydrogel. To the mechanics community, we show that, for the first time in hydrogels, the fatigue threshold depends only on the covalent network, but not on the noncovalent interactions that provide dissipation.
Imitating origami principles in active or programmable materials opens the door for development of origami-inspired self-folding structures for not only aesthetic but also functional purposes. A variety of programmable materials enabled self-folding structures have been demonstrated across various fields and scales. These folding structures have finite thickness and the mechanical properties of the active materials dictate the folding process. Yet formalizing the use of origami
Abstract: Brittle materials propagate opening cracks under tension. When stress increases beyond a critical magnitude, then quasistatic crack propagation becomes unstable. In the presence of several precracks, a brittle material always propagates only the weakest crack, leading to catastrophic failure. Here, we show that all these features of brittle fracture are fundamentally modified when the material susceptible to cracking is bonded to a hydrogel, a common situation in biological tissues.
Sungmin Hong, Dalton Sycks, Hon Fai Chan, Shaoting Lin, Gabriel P. Lopez, Farshid Guilak, Kam W. Leong, Xuanhe Zhao, Advanced Materials, 27, 4035-4040, 2015.
Cavitation can be often observed in soft materials. Most previous studies were focused on cavitation in an elastomer, which is under different mechanical loadings. In this paper, we investigate cavitation in a constrained hydrogel induced by drying. With taking account of surface tension and chemo-mechanics of gels, we calculate the free energy of the system as a function of cavity size. The free energy landscape shows double-well structure, analogous to first-order phase transition. Above the critical humidity, a cavity inside the gel is tiny.
The class started today. I'll be teaching fracture mechanics this semester. I'll be mostly using the class notes I wrote in 2010, but will post updated ones.
Hydrogels that undergo a volume phase transition in response to an
external stimulus are of great interest because of their possible use as
actuator materials. The performance of an actuator material is normally
characterized by its force–stroke curve, but little is known about the
force–stroke behavior of hydrogels. We use the theory of the ideal
elastomeric gel to predict the force–stroke curves of a
temperature-sensitive hydrogel and introduce an experimental method for
measuring the curve. The technique is applied to PNIPAm hydrogels with
low cross-link densities. The maximum force generated by the hydrogel
increases with increasing cross-link density, while the maximum stroke
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