Intermolecular hydrogen bonds in urea–water complexes: DFT, NBO, and AIM analysis

Hammami, Férid; Ghalla, Houcine; Nasr, Salah

doi:10.1016/j.comptc.2015.07.018

Cited by 46 publications

(18 citation statements)

References 42 publications

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“…All the humectant solutions slowed the rate of water loss compared with DI water. This is as expected as all the humectants hydrogen bond with the water molecules [12][13][14].…”

Section: Résultatssupporting

confidence: 81%

Understanding humectant behaviour through their water‐holding properties

Crowther¹

2021

Intern J of Cosmetic Sci

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Objective Humectants perform essential roles in the formulation of topical moisturizing products in terms of delivery of active ingredients, consumer experience and biophysical behaviour. How they retain and release water is key to understanding their behaviour. Methods Dynamic vapour sorption (DVS) was used to monitor the dehydration kinetics of three humectants widely used in topical formulations—glycerine, dexpanthenol and urea. Model aqueous solutions with concentrations of 20% w/w were tested and compared against pure deionized water. Results The three humectants varied in their ability to retain water during the dehydration process. Dexpanthenol was able to retain water most efficiently during the latter stages of dehydration. Urea demonstrated evidence of crystallization during the final stage of water loss, which was not shown by glycerine or dexpanthenol. Conclusions Humectants perform vital roles in the formulation of consumer acceptable topical products including the delivery of actives to the skin. Their ability to influence water movement in the skin is also essential for the maintenance of stratum corneum flexibility. DVS assessment of aqueous solutions has demonstrated how the behaviour of three commonly used humectants differs. Knowledge of the mechanisms by which these humectants operate enables the formulator to develop topical products optimized for the roles for which they are intended.

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“…All the humectant solutions slowed the rate of water loss compared with DI water. This is as expected as all the humectants hydrogen bond with the water molecules [12][13][14].…”

Section: Résultatssupporting

confidence: 81%

Understanding humectant behaviour through their water‐holding properties

Crowther¹

2021

Intern J of Cosmetic Sci

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“…DFT calculations can measure atoms or molecules' properties and structural properties based on electron density [10]. The DFT method was previously used in comprehensive research to study minor to large molecules [11][12][13]. However, due to its limitations, DFT studies on polymers usually use dimer structures [11,14].…”

Section: ■ Introductionmentioning

confidence: 99%

Density Functional Theory Study of Intermolecular Interactions between Amylum and Cellulose

et al. 2022

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Amylum is one of the polysaccharides developed into biodegradable plastic bags. However, amylum-based plastics are easily damaged due to their low mechanical strength and hydrophilic properties. Cellulose is used as a support material in amylum-based plastics to increase strength and reduce water damage. This study investigated the molecular interactions between amylum and cellulose computationally. The minimum interaction energy of amylum and cellulose was calculated using in silico modeling using the Density Functional Theory (DFT) method. The B3LYP function and the basis set 6-31++g** were used in the calculations. Simultaneously, D3 Grimme dispersion correction was used as the effect of water solvent in the measures. The results obtained from this study were the interaction energy of amylum and cellulose of –29.8 kcal/mol. The HOMO-LUMO energy gap of the cellulose-amylum complex was lower than cellulose, indicating that the cellulose-amylum complex was more reactive and bonded to each other. Analysis of Natural Bond Orbital (NBO), Quantum Theory Atom in Molecule (QTAIM), Reduced Density Gradient (RDG), Non-covalent Interaction Index (NCI), and Intrinsic Bond Strength Index (IBSI) showed that the cellulose-amylum complex had weak to medium intermolecular bonds. The hydrogen bond at O61···H48 was the strongest in the complex. All data show that cellulose and amylum could interact through non-covalent bonds.

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“…[44] Urea also forms strong hydrogen-bonded networks with itself and other compatible molecules. [45] Given that the HSA adhesion mechanism was attributed to protein denaturation (unfolding) and reorganisation into a strongly hydrogenbonded β-sheet rich conformation, we thought it would be interesting to investigate the effect of urea incorporation into the HSA formulation.…”

Section: Incorporating Urea Into the Formulationmentioning

confidence: 99%

Blood, Sweat and Tears: Extraterrestrial Regolith Biocomposites with in Vivo Binders

Roberts

Whittall²,

Breitling³

et al. 2021

Preprint

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In this work, we explore the use of human serum albumin (HSA) – a common protein obtained from blood plasma – as a binder for simulated Lunar and Martian regolith to produce so-called extraterrestrial regolith biocomposites (ERBs). In essence, HSA produced by astronauts in vivo could be extracted on a semi-continuous basis and combined with Lunar or Martian regolith to produce a concrete-like material. Employing a simple fabrication strategy, HSA-based ERBs were produced and displayed compressive strengths as high as 25.0 MPa. For comparison, standard concrete typically has a compressive strength ranging between 20 and 32 MPa. The incorporation of urea – which could be extracted from the urine, sweat or tears of astronauts – could further increase the compressive strength by over 300% in some instances, with the best-performing formulation having an average compressive strength of 39.7 MPa. Furthermore, we demonstrate that HSA-ERBs can be 3D-printed, opening up an interesting potential avenue for extraterrestrial construction using human-derived feedstocks. The mechanism of adhesion was investigated and attributed to the dehydration-induced reorganisation of the protein secondary structure into a densely hydrogen-bonded, supramolecular β-sheet network – analogous to the cohesion mechanism of spider silk. For comparison, synthetic spider silk and bovine serum albumin (BSA) were also investigated as regolith binders – which could also feasibly be produced on a Martian colony with future advancements in biomanufacturing technology.<br>

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Intermolecular hydrogen bonds in urea–water complexes: DFT, NBO, and AIM analysis

Cited by 46 publications

References 42 publications

Understanding humectant behaviour through their water‐holding properties

Understanding humectant behaviour through their water‐holding properties

Density Functional Theory Study of Intermolecular Interactions between Amylum and Cellulose

Blood, Sweat and Tears: Extraterrestrial Regolith Biocomposites with in Vivo Binders

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