Chemistry of cereal in milk
Surface tension, not hydrogen bonding, is the primary phenomenon which causes cereal rings such as Cheerios to adhere together while floating in milk.

The total linear perimeter of the 3-phase cereal-air-milk interface is minimized when pieces cling together.

Here are some links:


http://www.livescience.com/9350-cereal-science-floating-objects-stick.html
http://phys.org/news/2010-09-well-known-effect-breakfast-cereal-physicists.html
https://en.wikipedia.org/wiki/Cheerios_effect