We report on the nanostructure and morphology, as well as rheological and self-healing properties of hydrogen-bonded assemblies formed by the triblock copolymer Pluronics® F127 (F127) and polycarboxylic acids of varied hydrophobicity and chain length. In solution, the nanostructure and colloidal stability of the polyacid/F127 complexes (which occurred as stable dispersions, slowly coagulating dispersions, or precipitates) were dependent on the polycomplex composition and polyacid molecular weight and hydrophobicity, as well as temperature. The low-molecular-weight polyacrylic acid (PAA) formed nanosized, dispersed complexes in which the polyacid chains were wrapped around individual F127 micelles. Chemical crosslinking of PAA in the shells of these complexes followed by removal of the templating F127 cores resulted in easy-to-prepare, monodisperse, pH-responsive polymer nanocages with controllable size and swelling amplitude. The extrudable hydrogen-bonded polyelectrolyte assemblies were achieved with precipitates of poly(methacrylic acid) (PMAA)/F127 complexes obtained with high-molecular-weight PMAA. The elasticity and viscosity of PMAA/F127 complexes were determined by the extent of hydrogen bonding in the complexes, which could be manipulated <i>via </i>exposure to aqueous solutions at different pH levels and/or the aqueous solutions with different co-solvent concentrations. Under low-pH conditions, the PMAA/F127 complexes were readily extrudable from capillary dies, and the extrudates preserved their shape upon exiting the capillary. Furthermore, PMAA/F127 assemblies demonstrated a self-healing capability which could be manipulated by varying the strength of interpolymer association <i>via </i>solution pH.

Hydrogen-bonded complexes of a triblock Pluronic® copolymer with a weak polyacid: From nanocages to self-healing materials

254th National Meeting (2017)

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