It's relatively easy to get glue to stick in dry conditions, but it's much harder to get it to stay glued underwater. Still, a new bio-based glue not only works underwater but also gets stronger when submerged.
这种无毒粘合剂由印第安纳州普渡大学的古德伦-施密特（GudrunSchmidt）副教授及其同事研制。它主要由玉米蛋白（一种从玉米中提取的蛋白质）和单宁酸（从橡树树皮的虫瘿中提取）制成。
Sandwiching the glue between two objects and holding them under water will initially create a thin skin. Just prick it with your finger or something similar to break this thin layer of skin. In this way, surrounding water can enter the glue and increase its bonding strength. Adhesion is greatest when the water temperature is approximately 30ºC (86ºF).
While the exact cause of this reaction isn't entirely clear, Schmidt points out that tannic acid is the primary cause of adhesion to surfaces, and that the acid's molecules have similarities to those in the natural glue mussels use to adhere to rocks underwater. The entire gluing process is no different than preparing a hard-boiled egg.
施密特告诉我们："当你把一个生鸡蛋扔进温水中时，鸡蛋周围会形成一层明显的表皮，而里面还是生的。如果水温不高不低，鸡蛋周围的蛋皮就会很薄，用叉子尖就能轻易打破[......]如果你现在把水煮蛋挤在两片面包之间，那么你或多或少就完成了我们把一团胶水夹在两块基板之间的工作"。
The analogy goes a step further, if you heat a sandwich, the eggs will harden and hold the two slices of bread together.
Schmidt added that the glue is easy to make outside the laboratory from cheap, sustainable ingredients. It could eventually have applications in areas such as construction, biomedical/dental surgery, and even coral reef restoration.
A paper on the research was recently published in the journal ACS Applied Materials and Interfaces.