Micellisation and gelation of block-copoly(oxyethylene/oxybutylene/oxyethylene) E58 B17 E58

Luo, Yun‐Zhu; Nicholas, Christian V.; Attwood, David; Collett, John; Price, Colin; Booth, Colin

doi:10.1007/bf00652874

Cited by 57 publications

(39 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dependence of the Debye function Kc p /(I s ϪI so ) on concentration is similar to that reported previously for solutions of block copolymer micelles. 36,37 Intermicellar interference results in a deviation from the linear relation between the Debye function and c p usually observed in dilute solution, and can be accounted for using the equation,…”

Section: B Solution Structure: Saxs and Light Scatteringmentioning

confidence: 99%

“…The increased hydrophobicity ͑which the dehydration im-plies͒ gives a reduced cmc, and the micelle aggregation number N increases with T, which is shown by the increase in M w with T, in agreement with earlier reports. 36,[40][41][42] Examples of intensity fraction distributions obtained from analysis of the dynamic light scattering autocorrelation function using CONTIN are shown in Fig. 5.…”

Section: B Solution Structure: Saxs and Light Scatteringmentioning

confidence: 99%

See 1 more Smart Citation

The liquid–solid transition in a micellar solution of a diblock copolymer in water

Castelletto

Caillet

Fundin

et al. 2002

The Journal of Chemical Physics

View full text Add to dashboard Cite

The structure of a diblock copolymer solution in the vicinity of the transition between micellar liquid and solid phases was investigated using small-angle x-ray scattering ͑SAXS͒. An amphiphilic poly͑oxyethylene͒-poly͑oxybutylene͒ diblock was studied in water. Static and dynamic light scattering techniques were used to provide an independent measure of micelle dimensions and aggregation number. Dynamic shear rheometry and mobility measurements were used to locate phase transitions. A micellar liquid phase was identified at low concentration and a cubic micellar phase at higher concentration, the transition between the two occurring at higher temperature as the concentration increased. The cubic micellar phase behaves rheologically as a solid and SAXS confirmed a face-centered cubic structure. Intermediate between these two phases, a viscoelastic soft solid was observed, with a finite yield stress but with a much lower dynamic modulus than the crystalline solid. Several distinct suggestions have been put forward for the structure of the solution in this region. In a poly͑oxyethylene͒-poly͑oxypropylene͒-poly͑oxyethylene͒ Pluronic triblock, small-angle neutron scattering and rheology provided evidence for a percolation transition between micellar liquid and solid phases ͓L. Lobry et al., Phys. Rev. E. 60, 7076 ͑1999͔͒, indicating a fractal structure of micelles aggregated due to attractive interactions. Alternatively, a defective solid phase has been proposed. We analyzed the structure of solutions of our diblock copolymer via detailed model fits to the SAXS data for concentrations spanning the liquid-solid transition. The micellar form factor was modeled as a homogeneous micellar core with attached Gaussian chains; and the intermicellar structure factor could be described using the hard sphere model. Thus there is no evidence for percolation induced by effective attractive interactions between micelles in our system. In contrast SAXS data indicates there is a coexistence region between hard sphere fluid and solid crystal phases, in which small grains of close-packed crystal coexist with fluid. It is apparent that block copolymer micelles acts as model colloidal systems in which it is possible to investigate the influence of attractive and repulsive interactions between spherical particles by varying the copolymer composition.

show abstract

Section: B Solution Structure: Saxs and Light Scatteringmentioning

confidence: 99%

Section: B Solution Structure: Saxs and Light Scatteringmentioning

confidence: 99%

The liquid–solid transition in a micellar solution of a diblock copolymer in water

Castelletto

Caillet

Fundin

et al. 2002

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…The diblock or triblock copolymers of PEG and poly(butylene oxide) (PBO) show a similar phase transition behavior dependent on temperature, but they tend to associate more easily because of the more hydrophobic PBO compared with PPO. 4,8,9 However, these copolymers were found to induce the toxic enhancement of plasma cholesterol and triglycerol after intraperitional infection because they were nonbiodegradable and likely accumulated in the body. 11,12 Therefore, the temperature-sensitive biodegradable polymers consisting of PEG and biodegradable polyester such as poly(L-lactic acid) (PLLA), poly(D,L-lactic acid) (PDLLA), poly(lactic acid-coglycolic acid) (PLGA), and poly(DLLA-co-⑀-caprolactone) (PDLLA-co-PCL) have been investigated extensively in recent years.…”

Section: Introductionmentioning

confidence: 99%

Poly(D,L‐lactic acid‐co‐glycolic acid)‐b‐poly(ethylene glycol)‐b‐poly (D,L‐lactic acid‐co‐glycolic acid) triblock copolymer and thermoreversible phase transition in water

Shim

Lee

Shim

et al. 2002

J. Biomed. Mater. Res.

146

View full text Add to dashboard Cite

Novel thermoreversible gelation behavior of aqueous solutions of ABA-type triblock copolymers composed of the central polyethylene oxide (PEG) block and two poly(D,L-lactic acid-co-glycolic acid) side blocks was found. Phase transition characteristics, such as critical gel concentration (CGC) and lower and upper critical gel temperature (CGT), are closely related to the molecular structure of the triblock copolymers. The CGC and the lower CGT both increases with increasing PEG/PLGA molecular weight ratio. Increasing the GA content in PLGA block induces a somewhat higher CGC. The copolymer forms micelles with a PLGA loop core and a PEG shell in water. Also grouped micelles are identified seemingly due to the bridging of two micelles sharing two PLGA blocks of a block copolymer chain. As the temperature increases the association of micelles increases, which results in gelation. The ABA-type copolymers exhibit a relatively low CGC (<10%) and low sol-gel transition temperatures compared to BAB-type copolymers. As the temperature increases further gel-sol transition is observed, which would result from the shrinkage of micelles with temperature increase. The hydrodynamic size of the micelles is monitored by dynamic laser scattering, and a possible gelation mechanism was suggested.

show abstract

“…10 For PEO-PBO-PEO triblock copolymers, where poly(butylene oxide) (PBO) is introduced as the hydrophobic middle block, replacing the PPO block of Pluronics, a similar phase diagram has been observed in concentrated aqueous solutions. 11,12 Therefore, it is suggested that the structure of block copolymers demanded for such phase transition is not confined to PEO and PPO or to PEO and PBO if the balance between hydrophilicity and hydrophobicity in block copolymers is moderately adjusted. In recent reports, studies on thermoreversible gel-sol transition have been expanded to structurally varied block copolymer systems including PEO-aliphatic polyesters.…”

Section: Introductionmentioning

confidence: 99%

Phase-transition characteristics of amphiphilic poly(2-ethyl-2-oxazoline)/poly(?-caprolactone) block copolymers in aqueous solutions

Kim

Lee

Kang

et al. 2000

J. Polym. Sci. B Polym. Phys.

View full text Add to dashboard Cite

Micellisation and gelation of block-copoly(oxyethylene/oxybutylene/oxyethylene) E58 B17 E58

Cited by 57 publications

References 32 publications

The liquid–solid transition in a micellar solution of a diblock copolymer in water

The liquid–solid transition in a micellar solution of a diblock copolymer in water

Poly(D,L‐lactic acid‐co‐glycolic acid)‐b‐poly(ethylene glycol)‐b‐poly (D,L‐lactic acid‐co‐glycolic acid) triblock copolymer and thermoreversible phase transition in water

Phase-transition characteristics of amphiphilic poly(2-ethyl-2-oxazoline)/poly(?-caprolactone) block copolymers in aqueous solutions

Contact Info

Product

Resources

About