title: In situ characterization of structural dynamics in swelling hydrogels.
abstract: Characterizing the structural morphology and the local viscoelastic properties of soft complex systems raises significant challenges. Here we introduce a dynamic light scattering method capable of in situ, continuous monitoring of structural changes in evolving systems such as swelling gels. We show that the inherently non-stationary dynamics of embedded probes can be followed using partially coherent radiation, which effectively isolates only single scattering contributions even during the dramatic changes in the scattering regime. Using a simple and robust experimental setup, we demonstrate the ability to continuously monitor the structural dynamics of chitosan hydrogels formed by the Ag(+) ion-triggered gelation during their long-term swelling process. We demonstrate that both the local viscoelastic properties of the suspending medium and an effective cage size experienced by diffusing probe particles loaded into the hydrogel can be recovered and used to describe the structural dynamics of hydrogels with different levels of cross-linking. This characterization capability is critical for defining and controlling the hydrogel performance in different biomedical applications.
authors.affiliation: CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius St., Orlando, FL 32826, USA. adogariu@creol.ucf.edu.
authors.forename: J R
authors.initials: JR
authors.lastname: Guzman-Sepulveda
authors.affiliation: Department of Materials Science and Engineering, University of Central Florida, 12760 Pegasus Drive, Orlando, FL 32816, USA. Jiyu.Fang@ucf.edu.
authors.forename: J
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Materials Science and Engineering, University of Central Florida, 12760 Pegasus Drive, Orlando, FL 32816, USA. Jiyu.Fang@ucf.edu.
authors.forename: J Y
authors.initials: JY
authors.lastname: Fang
authors.affiliation: CREOL, The College of Optics and Photonics, University of Central Florida, 4304 Scorpius St., Orlando, FL 32826, USA. adogariu@creol.ucf.edu.
authors.forename: A
authors.initials: A
authors.lastname: Dogariu
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D055682:Viscoelastic Substances
chemical_list: D020100:Hydrogels; D055682:Viscoelastic Substances; D048271:Chitosan