Physically Cross-Linked Cryogels of Linear Polyethyleneimine: Influence of Cooling Temperature and Solvent Composition

Physically cross-linked cryogels can be prepared using linear polyethyleneimine (L-PEI) and a freeze-thawing technique. L-PEI was synthesized by hydrolysis of poly(2-ethyl-2-oxazoline) under acidic conditions. Dissolution in deionized water achieved at 80 °C resulted transparent solution, leading to the formation an opaque gel upon freezing subsequent thawing. The exhibited reversibility, after heating °C, they formed clear solution due melting crystalline domains L-PEI. effects different cooling temperatures use various solvent compositions on gelation were also studied. aqueous solutions (?196, ?80, ?30, 0 °C) for 3 h thawing 25 24 h. Gel rigidity correlated with temperature strongest when cooled down ?196 consistent determinations degree crystallinity gels, enthalpy fusion, rheological behavior. effect mixtures properties investigated. Water/ethanol containing higher proportion ethanol significantly reduced strength, viscosity, cryogels. Thus, controlling or modifying solvent, designed desired mechanical applications ranging from cell immobilization tissue culture scaffolds drug delivery systems antimicrobial wound dressings.