Interaction of poly(ethylene oxide) with solvents: 2. Water-poly(ethylene glycol)

Graham, N.B.; Zulfiqar, Muhammad; Nwachuku, N.E.; Rashid, Ayesha

doi:10.1016/0032-3861(89)90026-8

Cited by 123 publications

(113 citation statements)

References 24 publications

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“…Thus, when interacting with water, the PEGs give rise to a well-defined structure (3) in which the hydrogen bonding becomes the preponderant interaction. (1,4) Several structural models have been suggested in order to explain the high solubility of the PEGs. In the case of the lower molar mass PEGs, the oxygen ether can be directly involved through hydrogen bonds in the water lattice, (14) and the hydrophobic interaction mainly controls the solution behaviour.…”

Section: Discussionmentioning

confidence: 99%

Excess molar volumes and excess molar heat capacities of (polyethylene glycols + water) at temperatures betweenT=278 K andT=328 K

Aucouturier

Roux-Desgranges

Roux

1999

The Journal of Chemical Thermodynamics

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Section: Discussionmentioning

confidence: 99%

Excess molar volumes and excess molar heat capacities of (polyethylene glycols + water) at temperatures betweenT=278 K andT=328 K

Aucouturier

Roux-Desgranges

Roux

1999

The Journal of Chemical Thermodynamics

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“…28 The experimental values range between 0.5 and 6 water molecules per EO group, depending on the on the experimental technique applied, [54][55][56][57][58] with larger numbers associated with both direct and indirect (via water bridges) bound water. 54,56,59,60 …”

Section: Hydration Of Eo Chainsmentioning

confidence: 99%

Thermodynamics of the self-assembly of non-ionic chromonic molecules using atomistic simulations. The case of TP6EO2M in aqueous solution

et al. 2015

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(2015) 'Thermodynamics of the self-assembly of non-ionic chromonic molecules using atomistic simulations.The case of TP6EO2M in aqueous solution.', Soft matter., 11 (4). pp. 680-691. Further information on publisher's website:http://dx.doi.org/10.1039/C4SM02275KPublisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTAtomistic molecular dynamic simulations have been performed for the non-ionic chromonic liquid crystal 2,3,6,7,10,11-hexa-(1,4,7-trioxa-octyl)-triphenylene (TP6EO2M) in aqueous solution. TP6EO2M molecules consist of a central poly-aromatic core (a triphenylene ring) functionalized by six hydrophilic ethyleneoxy (EO) chains, and have a strong tendency to aggregate face-to-face into stacks even in very dilute solution. We have studied self-assembly of the molecules in the low concentration range corresponding to an isotropic solution of aggregates, using two force fields GAFF and OPLS. Our results reveal that the GAFF force field, even though it was successfully used previously for modelling of ionic chromonics, overestimates the attraction of TP6EO2M molecules in water. This results in an aggregation free energy which is too high, a reduced hydration of EO chains and, therefore, molecular self-assembly into compact disordered clusters instead of stacks. In contrast, use of the OPLS force field, leads to self-assembly into ordered stacks in agreement with earlier experimental studies of triphenylene-based chromonics. The free energy of association follows a "quasi-isodesmic" pattern, where the binding free energy of two molecules to form a dimer is of the order of 3 RT larger than the corresponding energy of addition of a molecule into a stack. The obtained value for the binding free energy, ∆ agg G 0 = -12 RT, is found to be in line with the published values for typical ionic chromonics (-7 to -12 RT), and agrees reasonably well with the experimental results for this system. The calculated interlayer distance between the molecules in a stack is 0.37 nm, which is at the top of the range found for typical chromonics (0.33-0.37 nm). We suggest that the relatively large layer spacing can be attributed to the repulsion between EO side chains.2

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“…The low molecular weight polymers exhibit a less ordered structure. 42,43 Spectroscopic studies showed that the polymer chain conformation in the aqueous solution is more ordered than that in organic solvent 44 or in the melt. 45 Analogously, the thermodynamic behaviour of PPGs 42 is similar to that of PEGs.…”

Section: (I) Adsorption Of Homopolymersmentioning

confidence: 99%

Adsorption of triblock copolymers and their homopolymers at laponite clay/solution interface. Role played by the copolymer nature

Lisi

Lazzara

Lombardo

et al. 2005

Phys. Chem. Chem. Phys.

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The adsorption thermodynamics of copolymers, based on ethylene oxide (EO) and propylene oxide (PO) units, at the laponite (RD) clay/liquid interface was determined at 298 K. The copolymer nature was tuned at molecular level by changing the hydrophilicity, the architecture and the molecular weight (Mw) keeping constant the EO/ PO ratio. Polyethylene (PEGs) and polypropylene (PPGs) glycols with varying Mw and their mixture were also investigated to discriminate the role of the EO and the PO segments in the adsorption process. Enthalpies of transfer of RD, at fixed concentration, from water to the aqueous macromolecule solutions as functions of the macromolecule molality were determined. They were treated quantitatively by means of a model based on two equilibria: (1) one-to-one binding between the macromolecule and the site on the solid and (2) two-to-one binding following which one macromolecule interacts with another one adsorbed onto the solid. The good agreement between the equilibrium constants obtained from calorimetry and those determined from kinetic experiments confirmed the reliability of the experimental and theoretical approaches. Almost all of the systems investigated are highlighted by the one-to-one binding; the L35 and 10R5 systems present both equilibria. The insights provided by the thermodynamics of adsorption of their homopolymers onto RD were fruitful in obtaining detailed information on the nature of the forces involved between RD and the copolymers. The data obtained in the present work clearly evidenced that for comparable polymer Mw, PPG is more suitable in building up a steric barrier around the RD particles and, indeed, exhibits several advantages and no drawbacks. Moreover, the parent copolymers may properly functionalize the RD surface by exploiting both their high affinity to the solid surface and the ability to self-assemble onto it as L35 and 10R5 clearly showed.

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Interaction of poly(ethylene oxide) with solvents: 2. Water-poly(ethylene glycol)

Cited by 123 publications

References 24 publications

Excess molar volumes and excess molar heat capacities of (polyethylene glycols + water) at temperatures betweenT=278 K andT=328 K

Excess molar volumes and excess molar heat capacities of (polyethylene glycols + water) at temperatures betweenT=278 K andT=328 K

Thermodynamics of the self-assembly of non-ionic chromonic molecules using atomistic simulations. The case of TP6EO2M in aqueous solution

Adsorption of triblock copolymers and their homopolymers at laponite clay/solution interface. Role played by the copolymer nature

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