Study of the State of the Triblock Copolymer Poly(ethylene oxide)−Poly(propylene oxide)−Poly(ethylene oxide) L64 in Aqueous Solution

Abstract

The state of the amphiphilic triblock copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) L64, (EO)13(PO)30(EO)13 (EO ) ethylene oxide, PO ) propylene oxide) in aqueous solution at concentrations below the critical micelle concentration (cmc) or temperatures below the critical micelle temperature (cmt) has been investigated by fluorescence probing using the fluorescent probe pyrene (fluorescence intensity ratio I1/I3, and fluorescence lifetime τ), ultrasonic absorption and conductivity. The effect of addition of sodium dodecyl sulfate (SDS) on the these properties was also investigated. The results suggest that at concentration below the cmc and at temperatures below the cmt, L64 aggregates under the form of small short-lived oligomers that are capable of binding pyrene and SDS. These oligomers probably involve the more hydrophobic components contained in the L64 sample investigated, which is polydisperse in composition like all amphiphilic block copolymers.

Dynamics of Micelles of Polyethyleneoxide-Polypropyleneoxide-Polyethyleneoxide Block Copolymers in Aqueous Solutions

“…The cmT values thus obtained are listed in Table 1 which also gives reported cmT values (6). The values from ultrasonic absorption are generally larger than the reported ones for reasons already discussed (7).…”

Probing competitive interactions in quaternary formulations

“…The effect of small molecule surfactants and alcohols on the aggregation behaviour of Pluronic P123 has been widely studied due to their extensive use in industry [1][2][3][4][5][6][7].…”

“…The mixed micelle aggregation number shows variations with changing the small molecule surfactant charge. For the P123/SDS system, the aggregation number decreases after adding SDS to the block copolymer (Nagg = 12 ± 5) [11,15,16,43], which is expected as the head group (SO4Na Figure 5 shows the variations in the scattering data at lower P123 and small molecule surfactant concentrations but at identical P123/surfactant ratio and above surfactants at the same composition, equation (4). For 0.5wt% P123-5 mM SDS, α(SDS) = 31 (±5)% [11], and for 0.5wt% P123-5 mM C12TAB, α(C12TAB) = 11 (±5)%.…”

“…A widely studied and practically relevant series of surfactants is the water soluble triblock copolymer group made up of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), denoted as (PEOn-PPOm-PEOn), commercially known as Pluronic (BASF), Synperonic (Croda) or Poloxamers (ICI) [1][2][3][4][5][6][7]. The CMC is sensitive to the chemical composition of the Pluronic and various grades are available.…”

Chemical analysis and aqueous solution properties of charged amphiphilic block copolymers PBA-b-PAA synthesized by MADIX®

“…This approach appeared sane and necessary for controlled radical polymerization samples, which are known to be imperfect. However, the same approach could also be enlightening with anionic polymerization samples, whose imperfections are not always negligible [5][6][7][8][9][10][11]. We have investigated samples of poly(butyl acrylate)-bpoly(acrylic acid), or PBA-b-PAA, synthesized by the Rhodia patented MADIX process [12].…”