Equation of State of Hydrogen-Bonded Polymer Solutions. Poly(propylene glycol) + <i>n</i>-Hexane and Poly(propylene glycol) + Ethanol

Colín, A. Crespo; Cancho, Susana M.; Rubio, Ramón G.; Compostizo, A.

doi:10.1021/ma961382p

Cited by 16 publications

(2 citation statements)

References 44 publications

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“…The lubricant poly[oxy(methyl-1,2-ethanediyl)] is soluble in ethanol at room temperature [37,38] and can be removed post-alignment if desired. Firstly, to increase adhesion of the nanowires to the PVA surface, the samples were pressed at room temperature using an electric rolling press (MSK-HRP-01, MTI Corporation, Richmond, CA).…”

Section: Lubricant Removalmentioning

confidence: 99%

Simple assembly of long nanowires through substrate stretching

2015

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Although nanowire (NW) alignment has been previously investigated, minimizing limitations such as process complexity and NW breakage, as well as quantifying the quality of alignment, have not been sufficiently addressed. A simple, low cost, large-area, and versatile alignment method is reported that is applicable for NWs either grown on a substrate or synthesized in solution. Metal and semiconductor NWs with average lengths of up to 16 μm are aligned through the stretching of polyvinyl alcohol (PVA) films, which compared to other stretching methods results in superior alignment because of the large stretching ratio of PVA. Poly[oxy(methyl-1,2-ethanediyl)] is employed as lubricant to prevent NW breakage. To quantify NW alignment, a simple and effective image processing method is presented. The alignment process results in an order parameter (S) of NW alignment as high as 0.97.

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Section: Lubricant Removalmentioning

confidence: 99%

Simple assembly of long nanowires through substrate stretching

2015

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“…In recent works we have carried out extensive experimental studies of the PÈoÈT surfaces of the systems PPG ] n-hexane, ]ethanol, and ]water. 25,26 Although it was possible to make a reasonable description of the experimental results for the non-aqueous systems using the lattice-Ñuid EoS of Panayiotou and Sanchez,27 the model did not describe the experimental data of the PPG ] water mixture. Therefore, there is a need to obtain experimental data on the equation of state of selected aqueous polymer systems which may be used for further theoretical progress.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of the equation of state and the surface tension of water-soluble polymers: poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) + water at 298.15 K

Compostizo

Cancho

Rubio

et al. 2001

Phys. Chem. Chem. Phys.

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The equation of state of poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (PEGÈPPGÈPEG) ] water has been measured in the sol phase at 298.15 K and up to 40 MPa. For the sake of comparison two mixtures of (PEG ] PPG) ] water, with the same PEG : PPG ratio as the copolymer, have been measured. The di †erences found between the data of the copolymer and the blend solutions are well beyond the experimental precision, the compressibility for the copolymer mixtures being larger than for the blend one. Contrary to previous non-aqueous mixtures, the aqueous ones present deviations with respect to the corresponding states equation proposed by the group of Sanchez (I. C. Sanchez, J. Cho and W. J. Chen, Macromolecules, 1993, 26, 4234). The surface tension c results show that both PEGÈPPGÈPEG and PPG are surface active, leading to a strong decrease of c with respect to that of water even for very low polymer concentrations. The behaviour of the spinodal pressure of the system is discussed in terms of the compressibility and the surface tension data.

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Microwave dielectric relaxation and molecular dynamics in binary mixtures of poly(vinyl pyrrolidone)–poly(ethylene glycol)s in non‐polar solvent

Sengwa

2003

Polymer International

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Dielectric relaxation study of binary mixtures of poly(vinyl pyrrolidone) (PVP) (M w = 40 000 g mol −1 ) and poly(ethylene glycol)s (PEGs) (M n = 200, 400 and 600 g mol −1 ) with concentration variation was carried out in dilute solutions of benzene at 10.1 GHz and 35 • C. The average relaxation time τ o , corresponding to segmental motion τ 1 and group rotations τ 2 was determined for PVP-PEGs mixtures. A comparison of these mixtures relaxation times was made with the relaxation times of PEGs in benzene solvent. The evaluated τ o values of PVP-PEGs mixtures in benzene solution are assigned to the reorientation of PEG molecules. It has been observed that the τ o value of PVP-PEG200 mixtures increases with increasing concentration of PVP but their values are small in comparison with the τ o value of PEG200 molecules. In the case of PVP-PEG400 and PVP-PEG600 mixtures, the evaluated values of τ o are greater than the corresponding τ o values of PEG400 and PEG600 molecules in benzene solvent. The variation in τ o values in these systems has been discussed by considering the stretching effect in the PEGs molecular chains in PVP-PEGs mixtures in benzene solutions. The high value of distribution parameter α (≈ 0.4 to 0.7) suggests that in these mixtures there is a large contribution of segmental motion and group rotations to the relaxation processes. The nature of the formation of hydrogen-bonded PVP-PEG complex heterogeneous network due to hydrogen bonding between carbonyl groups of PVP monomer units and terminal hydroxyl groups of PEGs is discussed. Furthermore, the elongation behaviour of PVP-PEG complex networks in benzene solvent and the molecular dynamics in the mixture due to breaking and reforming of hydrogen bonds has been explored by comparing the evaluated relaxation times and the Kirkwood correlation factor of pure PEG molecules for their possible use in drug control release systems. The relaxation times of these mixtures are independent of their viscosity, but the elongation of the mixture network is influenced by the PEG chain length and the number of hydroxyl groups in comparison with the number of carbonyl groups in the mixtures.

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Equation of State of Hydrogen-Bonded Polymer Solutions. Poly(propylene glycol) + n-Hexane and Poly(propylene glycol) + Ethanol

Cited by 16 publications

References 44 publications

Simple assembly of long nanowires through substrate stretching

Simple assembly of long nanowires through substrate stretching

Experimental study of the equation of state and the surface tension of water-soluble polymers: poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) + water at 298.15 K

Microwave dielectric relaxation and molecular dynamics in binary mixtures of poly(vinyl pyrrolidone)–poly(ethylene glycol)s in non‐polar solvent

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