Microstructure variations with concentration of propylene glycol–water solution probed by NMR

Zhou, Yan; Hu, Kai; Shen, Jian; Wu, Xiaojun; Cheng, Gongzhen

doi:10.1016/j.molstruc.2008.12.050

Cited by 9 publications

(10 citation statements)

References 24 publications

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“…Relatively little data, in comparison to that concerned with -OH moieties, have been published focusing on the behaviour of the alkyl group despite the role that this plays in determining liquid structure. 46 The alkyl functionality is particularly attractive for NMR studies as it allows for ready discrimination between water and 2-propanol and does not suffer from problems associated with 1 H-exchange between the two components. Elsewhere, this methodology has been applied to probe adsorbate-adsorbent interactions.…”

Section: Nmr Relaxation Time Analysismentioning

confidence: 99%

Structure and dynamics of aqueous 2-propanol: a THz-TDS, NMR and neutron diffraction study

McGregor

Zeitler

et al. 2015

Phys. Chem. Chem. Phys.

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Aqueous liquid mixtures, in particular, those involving amphiphilic species, play an important role in many physical, chemical and biological processes. Of particular interest are alcohol/water mixtures; however, the structural dynamics of such systems are still not fully understood. Herein, a combination of terahertz time-domain spectroscopy (THz-TDS) and NMR relaxation time analysis has been applied to investigate 2-propanol/water mixtures across the entire composition range; while neutron diffraction studies have been carried out at two specific concentrations. Excellent agreement is seen between the techniques with a maximum in both the relative absorption coefficient and the activation energy to molecular motion occurring at ∼90 mol% H2O. Furthermore, this is the same value at which well-established excess thermodynamic functions exhibit a maximum/minimum. Additionally, both neutron diffraction and THz-TDS have been used to provide estimates of the size of the hydration shell around 2-propanol in solution. Both methods determine that between 4 and 5 H2O molecules per 2-propanol are found in the 2-propanol/water clusters at 90 mol% H2O. Based on the acquired data, a description of the structure of 2-propanol/water across the composition range is presented.

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Section: Nmr Relaxation Time Analysismentioning

confidence: 99%

Structure and dynamics of aqueous 2-propanol: a THz-TDS, NMR and neutron diffraction study

McGregor

Zeitler

et al. 2015

Phys. Chem. Chem. Phys.

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“…This increased their relaxation time. According to Zhou et al, protons derived from bulk water have a higher mobility and their mobility decreases with an increase in the molar concentration of PG in the mixture, especially in the range of low PG concentrations [30].…”

Section: Detailed Description Of M8 Formulation Resultsmentioning

confidence: 99%

“…This could explain the difference between profiles obtained at 24 h and 48 h after dressing application. In mixtures of PG with water, Zhou et al have detected several proton fractions of different molecular mobilities depending on the molar concentration of PG [30]. They have observed the separate peaks in the magnetic resonance spectrum belonging to water and PG hydroxyls (triplet and doublet splitting).…”

Section: Detailed Description Of M8 Formulation Resultsmentioning

confidence: 99%

“…Consequently, at 48 h, two components in the MR signal across the dressing were present. Taking into account the spatial changes of the A 1d amplitude after 24 h of the experiment, i.e., higher at the contact plane than at the initial L values, a continuous water diffusion outside the dressing and its replacement with hydrated PG could be assumed [30]. At 48 h, after flattening profiles across both dressing and the substrate, an increase in T 2 relaxation time of both components was observed.…”

Section: Detailed Description Of M8_l Formulation Resultsmentioning

confidence: 99%

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In Vitro Wound Dressing Stack Model as a First Step to Evaluate the Behavior of Dressing Materials in Wound Bed—An Assessment of Mass Transport Phenomena in Hydrogel Wound Dressings

et al. 2021

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Wound dressings when applied are in contact with wound exudates in vivo or with acceptor fluid when testing drug release from wound dressing in vitro. Therefore, the assessment of bidirectional mass transport phenomena in dressing after application on the substrate is important but has never been addressed in this context. For this reason, an in vitro wound dressing stack model was developed and implemented in the 3D printed holder. The stack was imaged using magnetic resonance imaging, i.e., relaxometric imaging was performed by means of T2 relaxation time and signal amplitude 1D profiles across the wound stack. As a substrate, fetal bovine serum or propylene glycol were used to simulate in vivo or in vitro cases. Multi-exponential analysis of the spatially resolved magnetic resonance signal enabled to distinguish components originating from water and propylene glycol in various environments. The spatiotemporal evolution of these components was assessed. The components were related to mass transport (water, propylene glycol) in the dressing/substrate system and subsequent changes of physicochemical properties of the dressing and adjacent substrate. Sharp changes in spatial profiles were detected and identified as moving fronts. It can be concluded that: (1) An attempt to assess mass transport phenomena was carried out revealing the spatial structure of the wound dressing in terms of moving fronts and corresponding layers; (2) Moving fronts, layers and their temporal evolution originated from bidirectional mass transport between wound dressing and substrate. The setup can be further applied to dressings containing drugs.

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“…文献调研发现, 醇-水相互作用的 NMR 研究中, 选择的研究对象多为二醇, [19][20][21] 对一元醇和三元醇的相关分析并不多见, 不仅如此, 较多的文献仅限于对水分子的氧和氢的化学位移进行研究. 19,24 考虑到烷基质子化学位移的研究同样有助于了解醇水溶液中的氢键结构, 21,26…”

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<sup>1</sup>H NMR Investigation on Effect of Solute Concentration on the Hydrogen Bonding and Glass Transition of Three-Carbon Polyalcohol Aqueous Solutions

Yao¹,

Gao²,

Zhao³

et al. 2011

Acta Physico-Chimica Sinica

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We investigated the effects of solute concentration on the hydrogen bonding interactions of three-carbon polyalcohol aqueous solutions. In order to inspect the capacity of the solutions to form glass, proton nuclear magnetic resonance (1 H NMR) chemical shifts were determined in binary mixtures of water and 1-propanol (NPA), 2-propanol (IPA), 1,2-propanediol (PG), 1,3-propanediol (PD), and glycerol at room temperature and at atmospheric pressure using the external reference method. We found that the alkyl proton chemical shifts of PG with the CH3CH(OH)-group showed biphasic behavior, which was different from other molecules. Water molecules formed relatively strong O-H• • •O hydrogen bonds with the alcohol hydroxyls. The proton chemical shifts of H2O and the hydroxyl protons decrease with an increase in the number of alcohol hydroxyls at the same mole fraction. Moreover, the proton chemical shifts of H2O and hydroxyl protons with the same number of alcohol hydroxyls are different because of their different locations. The order of increased basicity agrees with the order of increased ice homogeneous nucleation suppression, that is, glycerol>PG>PD>IPA>NPA. This explains why glycerol and PG are more suitable as cryoprotective agents (CPAs) among the five polyalcohols.

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Microstructure variations with concentration of propylene glycol–water solution probed by NMR

Cited by 9 publications

References 24 publications

Structure and dynamics of aqueous 2-propanol: a THz-TDS, NMR and neutron diffraction study

Structure and dynamics of aqueous 2-propanol: a THz-TDS, NMR and neutron diffraction study

In Vitro Wound Dressing Stack Model as a First Step to Evaluate the Behavior of Dressing Materials in Wound Bed—An Assessment of Mass Transport Phenomena in Hydrogel Wound Dressings

<sup>1</sup>H NMR Investigation on Effect of Solute Concentration on the Hydrogen Bonding and Glass Transition of Three-Carbon Polyalcohol Aqueous Solutions

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