Perfluorooctanoic acid mediated self-assembly behaviour of linear and star block copolymer: An impact of intermolecular interaction on the polymer micelles

Abstract

In this communication, we present results from high sensitivity differential scanning calorimetry (HSDSC), dynamic light scattering (DLS), small-angle neutron scattering (SANS), and computational stimulation on the micellization and micelle morphology of two EO-PO block copolymeric surfactants, linear triblock copolymer Pluronic® F127 and star block copolymer Tetronic® T1107 (both with 70% PEO content) in the presence of perfluorooctanoic acid (PFOA). Increasing the concentration of PFOA in aqueous solutions of both copolymers resulted in a significant reduction in the critical micellization temperature (CMT), as inferred from calorimetric findings. Scattering experiments revealed intriguing results, indicating that the micelle radius (Rc, Rhs), and aggregation number (Nagg) of polymeric micelles increase with increasing PFOA concentration. The addition of PFOA does not alter the morphology of the micelles; however, comparing the correlation peaks in SANS suggests that the distance between the spherical micelles decreases as the PFOA concentration increases. Thus, the outcome of this study helps to fine-tune the performance-based properties of these widely used polymeric surfactants with a fluorinated hydrophobic additive.