Hydrogels with precisely designed structures represent promising materials with a broad application spectrum, such as for sensor, tissue engineering and biomimetic technology. However, with highly reactive compounds, ...Hydrogels with precisely designed structures represent promising materials with a broad application spectrum, such as for sensor, tissue engineering and biomimetic technology. However, with highly reactive compounds, the preparation of hydrogels still needs an efficient approach for desired distribution of each component within hydrogels. In addition, a method for in situ preparation of gradient hydrogels is still lacking. Herein, we report the formation ofhydrogels with either uniform or gradient internal structures via a novel, simple but very efficient method by aerating ammonia gas （NH3 gas） into the solution of dialdehyde cellulose （DAC） and a diamine. As-prepared hydrogels exhibited uniform microscopic and chemical structure or gradient distribution Of functional groups. Due to lots of aldehyde groups on DAC chains, functional hydrogels can be prepared by using diverse diamines. For instance, hydrogels prepared by using 1,6-hexanediamine as a cross-linker were responsive to pH values. Moreover, this controllable process of aerating NH3 gas allows the in situ formation of gradient hydrogels; for instance, by using cyanamide as a reaction counterpart, gradient hydrogels with gradient distributions of cyanide groups were prepared.展开更多
文摘Hydrogels with precisely designed structures represent promising materials with a broad application spectrum, such as for sensor, tissue engineering and biomimetic technology. However, with highly reactive compounds, the preparation of hydrogels still needs an efficient approach for desired distribution of each component within hydrogels. In addition, a method for in situ preparation of gradient hydrogels is still lacking. Herein, we report the formation ofhydrogels with either uniform or gradient internal structures via a novel, simple but very efficient method by aerating ammonia gas （NH3 gas） into the solution of dialdehyde cellulose （DAC） and a diamine. As-prepared hydrogels exhibited uniform microscopic and chemical structure or gradient distribution Of functional groups. Due to lots of aldehyde groups on DAC chains, functional hydrogels can be prepared by using diverse diamines. For instance, hydrogels prepared by using 1,6-hexanediamine as a cross-linker were responsive to pH values. Moreover, this controllable process of aerating NH3 gas allows the in situ formation of gradient hydrogels; for instance, by using cyanamide as a reaction counterpart, gradient hydrogels with gradient distributions of cyanide groups were prepared.
