Abstract

Gas phase coagulation is a highly efficient method for fabricating physically crosslinked nanochitin-based hydrogels. In this study, a visible and tailorable strategy was developed using phenolphthalein and litmus indicator. The indicator was applied to stain partially deacetylated nanochitin (DEChNs), ensuring that the gelation process occurring during gas phase coagulation was able to be clearly visualized. A semi-gelatinized interface cross-sectional view was obtained, leading to the possibility to monitor and optimize the crosslinking process. Thereafter, a series of optimizations was performed to improve the nanochitin gelation process. Only 16.5 h was required for sufficient physical crosslinking when the molar ratio of ammonia to acetic acid was 3.45. In mixtures containing this proportion, the ammonia solution was completely reduced and the formation process was able to be controlled and improved. A higher concentration of nanochitin led to a slower cross-linking process, but increased the mechanical strength and produced a more uniform structure, which might be due to the formation of a more uniform network at an appropriate gelation rate. The optimization of the physical cross-linking process will improve our understanding of the mechanisms underlying the gas phase coagulation technique and the control of the properties of nanochitin hydrogels and their composites by altering the cross-linking conditions.

Graphic abstract

The nanochitin gelation process was clearly visualized and optimized with substantially reduces the amount of ammonia solution and the precisely predicts and controls time, while it maintains a homogeneous and stable network structure, a higher specific surface and the same strong mechanical properties of the hydrogel.

中文翻译：

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通过酸碱指示剂染色，监测和优化，可视化和改善气相凝结过程中的物理胶凝过程

摘要

气相凝结是制备基于物理交联的纳米壳多糖的水凝胶的高效方法。在这项研究中，使用酚酞和石蕊指示剂开发了一种可见且可定制的策略。该指示剂用于染色部分脱乙酰化的纳米几丁质（DEChNs），以确保能够清楚地观察到气相凝结过程中发生的胶凝过程。获得了半糊化界面的横截面图，从而可以监控和优化交联过程。此后，进行了一系列优化以改善纳米几丁质凝胶化过程。当氨与乙酸的摩尔比为3.45时，充分的物理交联仅需要16.5 h。在含有该比例的混合物中 氨溶液被完全还原，形成过程得以控制和改进。较高浓度的纳米壳多糖导致较慢的交联过程，但是增加了机械强度并产生了更均匀的结构，这可能是由于在适当的胶凝速率下形成了更均匀的网络。物理交联过程的优化将改善我们对气相凝结技术基本机理的理解，并通过改变交联条件来控制纳米几丁质水凝胶及其复合材料的性能。这可能是由于在适当的胶凝速率下形成了更均匀的网络。物理交联过程的优化将改善我们对气相凝结技术基本机理的理解，并通过改变交联条件来控制纳米几丁质水凝胶及其复合材料的性能。这可能是由于在适当的胶凝速率下形成了更均匀的网络。物理交联过程的优化将改善我们对气相凝结技术基本机理的理解，并通过改变交联条件来控制纳米几丁质水凝胶及其复合材料的性能。

图形摘要

纳米甲壳素的凝胶化过程清晰可见，并进行了优化，大大减少了氨溶液的量，精确地预测和控制了时间，同时保持了水凝胶的均一和稳定的网络结构，较高的比表面积和相同的强机械性能。