Physically Cross-Linked Cryogels of Linear Polyethyleneimine: Influence of Cooling Temperature and Solvent Composition
Macromolecules(2022)
摘要
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 of L-PEI in deionized water was achieved at 80 degrees C and resulted in a transparent solution, leading to the formation of an opaque gel upon freezing and subsequent thawing. The cryogels exhibited reversibility, and after heating at 80 degrees C, they formed a clear solution due to the melting of the crystalline domains of L-PEI. The effects of different cooling temperatures and the use of various solvent compositions on L-PEI gelation were also studied. L-PEI cryogels were prepared by freezing aqueous solutions to various temperatures (-196, -80, -30, and 0 degrees C) for 3 h and subsequent thawing at 25 degrees C for 24 h. Gel rigidity correlated with the freezing temperature and was strongest when cooled down to -196 degrees C, consistent with determinations of the degree of crystallinity in the gels, the enthalpy of fusion, and rheological behavior. The effect of solvent mixtures on the crystallinity and rheological properties of L-PEI cryogels was also investigated. Water/ethanol mixtures containing a higher proportion of ethanol significantly reduced the strength, viscosity, and degree of crystallinity of the L-PEI cryogels. Thus, by controlling the freezing temperature or modifying the solvent, L-PEI cryogels can be designed with desired mechanical properties for applications ranging from cell immobilization and tissue culture scaffolds to drug delivery systems or antimicrobial wound dressings.
更多查看译文
关键词
linear polyethyleneimine,temperature,cross-linked
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要