Light scattering investigation of self-release polymeric derivatives

We describe the dynamics of new slow release formulations of plant growth regulators (PGR) in aqueous solution. The new PGR formulations are water-soluble copolymers derived from acrylamide and vinyl chloroethyl ether, containing side linkages of 1-naphthylacetic acid (NAA) and 3-indolbutyric acid (IBA). In discussing the results of the light scattering experiments we are interested primarily in the varying degree of the aromatic character of the side groups. The PGR system containing NAA hydrophobic side groups leads to the formation of interpolymeric micellar structures. The hydrodynamic radius, R-h, Of the parent polymer, almost doubles by incorporating the NAA linkages, but it remains approximately the same when the NAA linkages are replaced by IBA side groups of less aromaticity. The scattering intensities and apparent hydrodynamic radii display a systematic decrease as a function of time due to the loss of the IBA linkages in alkaline conditions. (C) 1998 Elsevier Science B.V. All rights reserved.