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pH‐ and Temperature‐Sensitive Chitosan Hydrogels: Swelling and MRI Studies
Author(s) -
Goycoolea Francisco M.,
FernándezValle María E.,
Aranaz Inmaculada,
Heras Ángeles
Publication year - 2011
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201000301
Subject(s) - self healing hydrogels , swelling , chitosan , microstructure , polymer , chemical engineering , drug delivery , porosity , materials science , chemistry , polymer chemistry , relaxation (psychology) , nanotechnology , composite material , organic chemistry , psychology , social psychology , engineering
MRI and swelling experiments are used to probe the state of water and infer the microstructure of chitosan hydrogels. SEM reveals a porous open scaffold‐type structure for hydrogels that were equilibrated at 2 °C before freezing as compared to those equilibrated at 37 °C. ADC MRI measurements reveal an anisotropy in the microstructure of these gels. T 1 relaxation MRI values were larger as the pH increased from 7.6 to 12.0, the result of a lower rate of exchange between protons of the hydration sphere of the polymer and bulk water. The thermosensitive and pH‐sensitive properties of these hydrogels can be utilized in the development of innovative materials for biotechnological and biomedical applications, including criobiocatalysis and bioremediation as well as in programmed drug delivery.