Regulating Volume Transitions of Highly Responsive Hydrogel Scaffolds by Adjusting the Network Properties of Microgel Building Block Colloids
"Entry by Pichet Adstamongkonkul, AP 225, Fall 2011"
Title: Regulating Volume Transitions of Highly Responsive Hydrogel Scaffolds by Adjusting the Network Properties of Microgel Building Block Colloids
Authors: E. C. Cho, J Kim, D. C. Hyun, U. Jeong, D. A. Weitz
Journal: Langmuir, 2008, Vol. 26, No. 6
In practice, it is desirable to have a hydrogel that rapidly responds to the applied stimulus. Many approaches have been exploited, including the addition of porosity, grafting extendable chains onto the polymer chains, or incorporating nanoparticles into the polymer network. However, the fast response is hard to achieved if the length of the hydrogels is at the macroscopic level, because the relaxation of the length is controlled by diffusion of liquid and is proportional to its dimension squared.
A new strategy uses sub-micrometer microgel particles as building blocks to assemble the 3D hydrogel network when heated above their transition temperature via bridging or depletion interactions. Considering the bulk properties of the scaffold, the degree of swelling can be controlled by changing the crosslinking density, which however changesthe response kinetics. To optimize the system, this study demonstrated that microgel particles may be the solution.