Physicochemical Investigation of the Micellar Behavior of a Diblock (PEO)62-b-(PBO)33 Copolymer in Water and its Interaction with Ionic Surfactants

The physicochemical investigations on the associative, micellar, and thermodynamic properties of a diblock (PEO)₆₂-b-(PBO)₃₃ copolymer in aqueous medium and its interaction with ionic surfactants were carried out by using surface tensiometry, laser light scattering, and steady-state fluorescence spectroscopy. Surface tension and fluorescence measurements were used to find out the critical micelle concentration (CMC) and related thermodynamic parameters of micellization copolymer at various temperatures. The data from dynamic light scattering (DLS) were helpful to obtain the values of hydrodynamic radii (R_h), volume (υ_h), and hydrodynamic expansion parameter (δ_h) of the copolymer micelle. Likewise, the measurements from static light scattering (SLS) were employed to determine weight-average molar (M_w), association number (N_w), thermodynamic radius (R_t), thermodynamic volume (υ_t), anhydrous volume (υ_a), and thermodynamic expansion parameter (δ_t) of the copolymer micelles in the temperature range of 20–50°C. Similarly, the interactions between (PEO)₆₂-b-(PBO)₃₃ and two ionic surfactants, sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (CTAB), have also been investigated by fluorescence spectroscopy and DLS at 30°C. Similarly, the interactions between (PEO)₆₂-b-(PBO)₃₃ and two ionic surfactants, sodium dodecyl sulfate and hexadecyl trimethylammonium bromide, have also been investigated by fluorescence spectroscopy and DLS in detail.