Micellar assembly leading to structural growth/transition in normal and reverse Tetronics® in single and mixed solution environment

• Published in: Soft matter Vol. 18; no. 24; pp. 4543 - 4553
• Main Authors: Patel, Dhruvi, Ray, Debes, Aswal, Vinod K, Kuperkar, Ketan, Bahadur, Pratap
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 22.06.2022
• Subjects: Aging; Ambient temperature; Antitumor agents; Aqueous solutions; Block copolymers; Coils; Ethylene oxide; Hydrophobicity; Light scattering; Micelles; Neutron scattering; Photon correlation spectroscopy; Propylene oxide; Self-association; Solubilization; Spectroscopy; Structure factor
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/d2sm00321j

This study scrutinizes the self-association of ethylene oxide (EO)-propylene oxide (PO)-based star-shaped block copolymers as normal Tetronic® (T904) and reverse Tetronic® R (T90R4) with varying molecular characteristics and different hydrophilic-hydrophobic ratios in an aqueous solution environment. These thermo-responsive solutions appear clear, transparent or bluish up to 10%w/v, which anticipated the probable transition of unimers to spherical or ellipsoidal micelles which is complemented by scattering experiments. In a single-solution environment, 10%w/v T904 formed star-shaped micelles at ambient temperature and exhibited a micellar growth/transition with temperature ageing. While 10%w/v T90R4 exists as unimers or a Gaussian coil over a wide range of temperature. Very interestingly, close to the cloud point (CP) flower-shaped spherical and ellipsoidal micelles were formed. A similar proposed micellar scheme was also examined for mixed systems T904 : T90R4 in varying ratios (1 : 0, 3 : 1, 1 : 1, 1 : 3 and 0 : 1) giving an account to the solution behavior of the mixtures. An amalgamation of dynamic light scattering (DLS) and small-angle neutron scattering (SANS) techniques achieved the thorough extraction of the structural parameters of the micellar system. The hydrodynamic diameter ( D h ) of the micelles with temperature variation was evaluated from dynamic light scattering (DLS) while the structure factor of the micelles was found by employing small-angle neutron scattering (SANS). Furthermore, the single and mixed micellar systems were quantitatively and qualitatively examined for anticancer drug solubilization using UV-vis spectroscopy for their superior use as potential nanocargos. Untying thermoresponsive self-association illustrating the micellar growth/transition in branched block polyether Tetronics ® with alternating blocks in single and mixed aqueous solution.