Journal Article Research Support, Non-U.S. Gov't hydrogen bond Density functional theory Hirshfeld Hydrogels Information theory Molecular acidity Molecular electrostatic potential Multiwfn Natural atomic orbital Review binding energy cell microenvironments cluster correlation analysis coupled cluster electron density hydrogels hyperpolarizability independent gradient model interaction region indicator mechanical cues noncovalent interaction nonlinear optical pi-pi stacking polymeric design quantum theory of atoms-in-molecules semiconductor spatiotemporal control