Breakdown kinetics of aggregates from poly(ethylene glycol‐bl‐propylene sulfide) di‐ and triblock copolymers induced by a non‐ionic surfactant

Abstract

We explored the effects of addition of the nonionic surfactant Triton X‐100 on the stability of aggregates of poly(ethylene glycol‐bl‐propylene sulfide) di‐ and triblock copolymers. Fluorescence spectra of pyrene, used as a probe molecule, elucidated the various stages of transformation from pure copolymeric micelles to surfactant‐rich micelles. Turbidity measurements yielded insight into the mechanism of the interaction, the hydrophobicity of the copolymer driving the process. Triton X‐100 tends to strongly interact with highly hydrophobic copolymers by inserting into the core of the micellar aggregates. On the other hand, Triton X‐100 tends to interact with the corona of micelles formed by less hydrophobic copolymers which, for this reason, are more stable upon addition of this destabilizing agent. Kinetic data give evidence that only monomers, not micelles of surfactant, interact with the copolymer micelles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2477–2487, 2008

How Detergents Dissolve Polymeric Micelles: Kinetic Pathways of Hybrid Micelle Formation in SDS and Block Copolymer Mixtures

“…Furthermore, the critical aggregation concentration (cac) of SDS may be different to the cmc, as there are also polymers present in the system. These results show that the solubilization process is in fact a combination of two processes, which is at odds with the findings by Cerritelli et al, who found first-order kinetics with only monomers of the surfactant interacting with the polymer micelles as the rate leveled off near the cmc. In our study, we see a significant acceleration for both concentration studies above the cmc, indicating a fusion/fission mechanism between the surfactant and polymer micelles.…”

“…To the best of our knowledge, only two studies have explored the solubilization kinetics of amphiphilic polymeric micelles through the addition of a surfactant. Cerritelli et al used fluorescence spectroscopy and turbidity measurements to investigate di- and triblock copolymers of the type poly­(ethylene oxide)– bl -poly­(propylene sulfide) (PEO-PPS), which forms mixtures of micelles and rods, upon the addition of a nonionic surfactant, Triton X-100. These authors found first-order kinetics with respect to the surfactant concentrations.…”

Comparative Investigations on In Vitro Serum Stability of Polymeric Micelle Formulations

“…In addition, we were able to achieve complete dye release after incubation from the still intact polymeric micelles by addition of 7.5% v/v TritonX-100 at 37°C. This non-ionic surfactant leads to the dissolution of polymeric micelles, as indicated by Cerritelli et al for PEG-PPS micelles (17). The resulting FRET ratio after complete dye release and the initial ratio enable the calculation of two parameters reflecting the stability of micelles: the in vitro serum half-life and residual micellar fraction (RMF).…”

Assessing the Role of Poly(ethylene glycol-bl-propylene sulfide) (PEG-PPS) Block Copolymers in the Preparation of Carbon Nanotube Biocompatible Dispersions

“…Numerous papers have already been published on the preparation, bioapplications, , and self-aggregation , of a new class of biocompatible block copolymers, structurally related to Pluronics, the triblock poly(ethylene glycol- bl -propylene sulfide- bl -ethylene glycol) and the diblock poly(ethylene glycol- bl -propylene sulfide) copolymers, referred to as PEG-PPS diblock and triblock copolymers, respectively (Chart b,c respectively). The PEG-PPS triblock system is analogous to the well-characterized Pluronics; however, the replacement of the oxygen atom in the chain backbone of poly(propylene glycol) with the sulfur atom of PPS renders the central block considerably more hydrophobic and presumably more prone to interact with the hydrophobic surface of the nanotubes.…”