Abstract: An expandable absorbent structure comprises an expansion loop core configured to expand in response to absorption of a liquid and an expansion loop material structure surrounding the expansion loop core and having a trough therein, wherein the trough is formed from a first portion of the expansion loop material structure folded over a second portion of the expansion loop material structure at a first elbow of the expansion loop material structure. In response to an increase in size of the expansion loop core, the expansion loop core presses against the expansion loop material structure to cause a length of the trough to decrease.