NONSPECIFIC INTERACTIONS IN POLYMER POLYMER REACTIONS .1. COMPLEX-FORMATION BETWEEN POLYCARBOXYLIC ACIDS AND 5-NITRO-8-QUINOLINOXYL DERIVATIVES OF POLYETHYLENE GLYCOLS

Complex formation between polyacrylic and polymethacrylic acids with the 5-nitro-8-quinolinoxyl derivatives of polyethylene-glycols (PEG) in dilute aqueous solutions has been studied by potentiometric titration and viscometry. The presence of terminal 5-nitro-8-quinolynoxyl groups results in a significant decrease in the critical chain length of the PEG necessary for the formation of stable complexes. The higher stability of these polycomplexes is probably determined by the additional reduction in the free energy of the system because of the nonspecific interaction of the 5-nitro-8-quinolinoxyl groups with the hydrophobic regions of the polycomplex. This type of nonspecific interaction has a more general character and could play an important role in the reactions of biopolymers in living systems.