Why is a polyethanol chain that has 100% -OH groups insoluble in water?
I have not heard of polyethanol, but if it exists it could have a similar structure to starch or cellulose, which are insoluble in water. The reason for this has to be hydrogen bonding. Two molecules of the same polyhydroxy substance will be bound together through hydrogen bonding on their -OH groups. The only reason a substance is soluble in water is that the forces binding it to water are greater than the forces binding its own molecules together (roughly speaking). So cellulose, for instance, is strongly bound in long strands, whereas starch is less well bound and on heating, forms a gel or a solid solution. Hope this helps.
