Investigation of hydrogen bonds in alkyl glycerol ethers

Atovmyan, E. G.; Koshchii, S. V.; Fedotova, T. N.

doi:10.1007/bf00662002

Cited by 3 publications

(10 citation statements)

References 5 publications

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“…It does not mean the free O−H state gives higher energy hydrogen bonding, it merely shows that free O−H vibrations (both in 3-OH and 2-OH positions) are not constrained by any hydrogen bonding, so they absorb the higher frequency infrared radiation. The O−H bonding bands of MGs and other compounds are in agreement with the relevant literature data. , Compared with the dry MG−oil sample, after heating, there is a broad peak at 3400 (1/cm) to show the bonding between MG and water. − It suggests that most MGs prefer to form the hydrogen bond with the water molecules rather than with each other in the initial state. During aging, the absorption band splits into three.…”

Section: Agingsupporting

confidence: 85%

“…To study hydrogen bonds, we focus on the low-energy region from 3000 to 4000 (1/cm). 39 In our recent study of hydrophobic MG-oil systems, we have established that the vibration mode of 2-OH bonds is at 3250 (1/cm), while the 3-OH stretching bond vibration is at 3300 (1/cm) (see Figure .8a). 23,39,40 3-OH hydrogen bonding is not a stable intermolecular link and only plays a subsidiary role in MG structuring.…”

Section: Agingmentioning

confidence: 89%

“…In our recent study of hydrophobic MG−oil systems, we have established that the vibration mode of 2-OH bonds is at 3250 (1/cm), while the 3-OH stretching bond vibration is at 3300 (1/cm) (see Figure ,, 3-OH hydrogen bonding is not a stable intermolecular link and only plays a subsidiary role in MG structuring. The 2-OH hydrogen bonds form and force MG to rearrange in a more ordered way.…”

Section: Agingmentioning

confidence: 99%

“…The aging of MG−oil−water was recorded by infrared spectroscopy, focusing on the change in the hydrogen bonding patterns. To study hydrogen bonds, we focus on the low-energy region from 3000 to 4000 (1/cm) . In our recent study of hydrophobic MG−oil systems, we have established that the vibration mode of 2-OH bonds is at 3250 (1/cm), while the 3-OH stretching bond vibration is at 3300 (1/cm) (see Figure…”

Section: Agingmentioning

confidence: 99%

“…After one week, the lower-frequency bands become sharper and increase their intensity (see Figure b). Over 16 days, the 2-OH bonding becomes dominant, which can only occur is D and L isomers were separated, as required for the formation of anhydrous β-crystals. − …”

Section: Agingmentioning

confidence: 99%

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Effects of Water on Aggregation and Stability of Monoglycerides in Hydrophobic Solutions

Chen

Terentjev

2009

Langmuir

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We apply a set of different techniques to analyze the physical properties and phase transitions of monoglyceride (MG)-oil-water ternary systems. The effect of MGs on water absorption in food-grade hazelnut oil and in pure hydrocarbon oil (decane) is reported. Comparison between decane and hazelnut oil backgrounds indicates that the effect of water absorption is significant and universal in different MG ternary systems. Adding small amounts of cosurfactant (stearic acid) is necessary to stabilize the MGs in oil-water combinations by enhancing the swelling capacity of lamellar layers; as a result, the structures become sensitive to the pH of the aqueous phase used. The dramatic changes on increasing the aqueous content are recorded by the calorimetry. In samples with small quantities of water, the phase behavior is almost independent of the pH. Once the proportion of water increases, the effect of pH is prominent. At low pH, the solubility of MG in water is limited, and the ternary system retains key features of the oil-dominated environment, such as the sequence of two transitions on cooling, with the low-temperature sub-alpha crystalline phase. At high pH and a sufficient amount of water, the MG layers remain properly swollen, and the crystalline phase disappears from the phase diagram. We spend considerable effort identifying the inverse lamellar phase of MGs in an oil-dominated environment with the so-called alpha-gel phase that is well-established in water-dominated systems, and distinguishing "demixing" from water and from oil. The rheology is examined in different fluid and gel phases; the storage modulus generally decreased on increasing the water proportion, but a gel-like response is found in the high-temperature lamellar phase over a wide range of water dilution. We then focus on aging phenomena in the inverse lamellar (or alpha-gel) phase and show that the rearranging of hydrogen bonds is slowed down and disrupted by the presence of water, giving the lamellar gel longer life times.

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Section: Agingsupporting

confidence: 85%

Section: Agingmentioning

confidence: 89%

Section: Agingmentioning

confidence: 99%

Section: Agingmentioning

confidence: 99%

Section: Agingmentioning

confidence: 99%

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Effects of Water on Aggregation and Stability of Monoglycerides in Hydrophobic Solutions

Chen

Terentjev

2009

Langmuir

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On the strategies for incorporating nanosilica aqueous dispersion in the synthesis of waterborne polyurethane/silica nanocomposites: Effects on morphology and properties

Peruzzo

Anbinder

Pardini

et al. 2016

Materials Today Communications

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Aging and Metastability of Monoglycerides in Hydrophobic Solutions

Chen

Terentjev²

2009

Langmuir

126

104

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The aging of aggregated structures of monoglycerides in hydrophobic medium is described by a set of different techniques. Polarized microscopy was used to study the mesomorphic behavior as a function of time. Differential scanning calorimetry was utilized to quantitatively monitor changes in the latent heat in different phase transformations that take place in the aging system. Infrared spectroscopy was applied to detect the formation of hydrogen bonding between surfactants. The X-ray diffraction patterns fingerprinted the molecular arrangement in different emerging phases. Infra-red spectroscopy was used to monitor the state of hydrogen bonding in the system. We conclude that in both inverted-lamellar and sub-alpha crystalline phases, monoglyceride molecules inevitably lose their emulsified ability in the hydrophobic solutions through the gradual change in hydrogen bonding patterns. On aging, the formation of intermolecular hydrogen bonding between glycerol groups causes the segregation of chiral (D and L) isomers within the bilayers. Therefore all structures were eventually forced to reorder into the betacrystalline state, distinguishing between the D and L layers. Accordingly, the highly ordered packing of aged structures weakened the emulsifying ability and finally leaded the collapse of the percolating gel network.

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Investigation of hydrogen bonds in alkyl glycerol ethers

Cited by 3 publications

References 5 publications

Effects of Water on Aggregation and Stability of Monoglycerides in Hydrophobic Solutions

Effects of Water on Aggregation and Stability of Monoglycerides in Hydrophobic Solutions

On the strategies for incorporating nanosilica aqueous dispersion in the synthesis of waterborne polyurethane/silica nanocomposites: Effects on morphology and properties

Aging and Metastability of Monoglycerides in Hydrophobic Solutions

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