Described herein is the synthesis of adhesive from simple adhesive coacervates and their uses thereof. The adhesives are composed of (a) a polyanion in the absence of a polycation, wherein the polyanion comprises at least one crosslinking group capable of covalently crosslinking with itself, and (b) a sufficient amount of a complimentary multivalent cation or multivalent anion to produce the simple coacervate. The adhesives have numerous medical and non-medical applications.