Preparation protocol of urea cross-linked chitosan aerogels with improved mechanical properties using aqueous aluminum ion medium

Chitosan has drawn tremendous interest in both academic and industrial fields due to its non-toxicity, antibacterial activity, biodegradability and high biocompatibility. This work presents a method to synthesize a class of chitosan aerogels with improved mechanical properties, deriving from chitosan sols in an aqueous aluminum ion medium. The initial urea concentration had a significant effect on the microstructure of chitosan aerogels. The pores in chitosan aerogels with low concentrations were primary mesoporous, for high urea concentrations the pores were dominated by macropores. Besides, the obtained chitosan aerogels can sustain a compressive strain of 80% without fracture or cracks and recover 5–15%. Thus, this work can provide a reference for preparation of chitosan aerogels with improved mechanical properties in the future.