Antifreezing Heat-Resistant Hollow Hydrogel Tubes

Hollow hydrogel tubes that are capable of maintaining their flexibility and structural stability in extreme temperature conditions have potential for use in biomedical scaffolds, carriers, and soft robotics over a wide temperature range. However, the preparation of hollow hydrogel tubes still remains challenging because it normally requires templates or complex devices and it is hard to endow the hollow tubes with antifreezing heat-resistant capabilities. We report a protocol that does not require a template or complex devices, in which sodium alginate film strips are immersed in an aqueous mixture of CaCO3, CaCl2, NaHCO3, and HCl, which results in the manufacture of hollow tubes in 30 min. These hollow tubes are functionalized by glycerol and poly(ethylene glycol), which provides the tubes with antifreezing heat-resistant performances and enables them to keep their flexibility and hollow structures from -70 to 120 degrees C. This is the first report on antifreezing heat-resistant hollow hydrogel tubes, to the best of our knowledge. Such hollow tubes as carriers can control the sublimation of a mothball at a rate of 1.1 mg/h, which is one-tenth of the sublimating rate of an unloaded mothball. This sublimating rate reduces the hazard to environments along with maintaining the repellent effects. As the tube is a honey carrier, it enables the sustainable release of the honey over 800 min with a high efficacy for tricking and capturing ants. The simple applications demonstrate that the antifreezing heat-resistant hollow tubes might be feasible as carriers for the controlled release in extremely cold/hot environments.

在极端温度条件下能够保持柔韧性和结构稳定性的中空水凝胶管在宽温度范围内具有用于生物医学支架、载体和软体机器人的潜力。然而，中空水凝胶管的制备仍然具有挑战性，因为这通常需要模板或复杂的设备，并且很难赋予中空管抗冻耐热能力。我们报道了一种不需要模板或复杂设备的方法，将海藻酸钠薄膜条浸入碳酸钙、氯化钙、碳酸氢钠和盐酸的水溶液混合物中，可在30分钟内制造出中空管。这些中空管通过甘油和聚乙二醇进行功能化，使其具有抗冻耐热性能，能够在-70℃到120℃之间保持柔韧性和中空结构。据我们所知，这是关于抗冻耐热中空水凝胶管的首次报道。这种作为载体的中空管能够以1.1毫克/小时的速度控制樟脑丸的升华，这是未负载樟脑丸升华速度的十分之一。这种升华速度在保持驱虫效果的同时降低了对环境的危害。由于该管是蜂蜜载体，它能够在800分钟以上持续释放蜂蜜，对诱捕蚂蚁具有高效能。这些简单的应用表明，抗冻耐热中空管作为在极寒/极热环境中控制释放的载体可能是可行的。