Controlling the aqueous growth of urea crystals with different growth inhibitors: a molecular-scale study

Singh, M. K.

doi:10.1039/d0ra10401a

Cited by 7 publications

(24 citation statements)

References 101 publications

(170 reference statements)

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“…The ratio of the growth rate between (001) and (110) becomes closer to unity in the presence of biuret, which leads to the formation of a crystal of low aspect ratio as observed experimentally. , Acetone exerts the weakest effect among the additives examined. The crystal morphology is then not changed appreciably, in agreement with the results in previous studies. ,, …”

Section: Resultsmentioning

confidence: 99%

“…The crystal morphology is then not changed appreciably, in agreement with the results in previous studies. 15,27,73 The structure and dynamics in the (steady) growth of the crystal can be described by N cry (t) of eq 1, n o (m o , mode; t) of eq 2, ⟨n(m s , m o , mode)⟩ as the time average of eq 3, and v(m s , m o , mode; Δt) of eq 7. They are shown in Figures 3−6 in the systems without additives and are provided in Figures 7 and S4−S6 in the presence of the additive species.…”

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

“…The adsorption on the urea surface was also examined with electronic-state calculations, and common tendencies with respect to the surface configuration were observed. 20,27 We next analyze the connection of Δμ ads to the extent of inhibition of the crystal growth. The effect of the additive on the overall growth was quantified with R(Δt) provided in Figures 8 and S7, while the "up" and "down" modes of the (001) face were not distinguished in R(Δt).…”

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

“…Molecular dynamics (MD) simulation can be a method of choice for analyzing the solid–liquid interface. It can describe atomic details of a solid surface in coexistence with liquid and has now proven to be useful for examining the intermolecular interactions in the growth and dissolution of a crystal and the adsorption on the interface with the liquid. − The performance was demonstrated for the force fields of urea, glycine, and pharmaceutically relevant compounds, and the dissolution was simulated with assessment of the dependence on the shape and face of the crystal. ,,− ,, The growth mechanism was addressed for urea crystal in contact with water, and the inhibition due to additives was analyzed in terms of their interactions on the crystal surface. ,,,, An efficient scheme to compute the free energy of adsorption was further formulated with the energy-representation theory of solvation, and the interaction component that leads to favorable adsorption was identified for the (001) and (110) faces of urea . All-atom analysis with MD is thus feasible reliably for a solid–liquid interface consisting of small molecules, and may provide molecular-level insights exceeding the experimental.…”

Section: Introductionmentioning

confidence: 99%

“…The additives studied are biuret, acetone, and N , N -dimethylformamide (DMF). Biuret has been used to modulate the morphology of the urea crystal, ,,, and acetone has nonpolar moieties with the structural framework similar to urea. DMF is examined because it is between biuret and acetone in terms of the polarity.…”

Section: Introductionmentioning

confidence: 99%

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Crystal Growth of Urea and Its Modulation by Additives as Analyzed by All-Atom MD Simulation and Solution Theory

et al. 2022

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The crystal growth of urea was analyzed with all-atom molecular dynamics (MD) simulation for the (001) and (110) faces in contact with aqueous solutions. The local environment of a crystallizing molecule was treated in terms of the numbers of crystalline neighbors and the orientation relative to the crystal surface, and the molecular-level inhomogeneity of a growing surface was addressed by decomposing the overall rate of growth into a sum of the contributions conditioned by the local structure and orientation mode. The contrast of the growth mechanism between the (001) and (110) faces was then evidenced by the local contributions, and the roles of the outer layers of the crystal toward the liquid region were pointed out for (001). The effect of the additive species in the liquid on the crystal growth of urea was investigated with biuret, N,N-dimethylformamide (DMF), and acetone. The growth was observed to be suppressed more strongly in the order of biuret > DMF > acetone, and it was found that the ordering of suppression by the additive is common irrespective of the local environment of a crystallizing urea. This finding implies that the additive’s effect on the crystal growth can be predicted by treating the flat surface, which is a convenient system for detailed analyses at atomic resolution. The correspondence to the free energy of adsorption of the additive was then examined for the additive-induced modulation of the growth rate. It was seen that the adsorption free energy correlates to the extent of modulation of the growth rate, and the interaction components that govern the adsorption propensity were identified.

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Section: Resultsmentioning

confidence: 99%

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

Section: The Journal Of Physical Chemistrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Crystal Growth of Urea and Its Modulation by Additives as Analyzed by All-Atom MD Simulation and Solution Theory

et al. 2022

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Morphology Regulation of Organophosphate Crystals by Micro‐Jetting Technique

Yang,

Guo

et al. 2024

Part & Part Syst Charact

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Organophosphates nucleating agents are widely used in the plastics industry. Nucleating agents with different morphologies have various effects on the resin materials. The micro‐jetting technique is shown to be a promising tool for the controlled preparation of micro‐and nano‐sized particles. Therefore, in this paper, controllable preparation of sodium 2,2'‐methylene‐bis‐(4,6‐di‐tert‐butylphenyl) phosphate (NA11) is achieved by the micro‐jetting technique. The study focused on the impact of various parameters on its shape and size. Hexagonal, rhombic, rod‐shaped, and needle‐shaped micro‐sized NA11 crystals are prepared. The results show that the decrease in the polarity of the organic solvents added in the antisolvent water led to the transformation of NA11 from bulk hexagon to plate‐like rhombus and finally to needle‐shaped crystals. The addition of surfactants can regulate the crystal growth rates and orientations, thereby facilitating the formation of rod‐shaped crystals. Based on rod‐shaped crystals, the crystal size is studied. Crystals with average particle sizes in the range of 40–100 µm can be obtained with coefficients of variation as low as 4% by varying the relevant experimental parameters such as the supersaturation, the solution homogeneity in the crystal growth environment, and the mixing intensity. This study provides references for designing functional materials.

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Role of Different Solvents and Tailor-Made Additives in Asymmetry in Growth Rates along the Opposite Ends of the Polar Axis: The Riddle of α-Resorcinol

Singh

Banerjee

2022

Crystal Growth & Design

Self Cite

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Understanding the mechanism of unidirectional growth of polar acentric materials along the polar axis has been an important issue so far. To this end, we computationally examine the role of various tailor-made additives in aqueous, acetic acid, and acetone solutions to elucidate the underlying mechanism of asymmetry in the growth of α-resorcinol crystals. A simulated annealing method followed by periodic density functional theory using the B3LYP method augmented with an empirical dispersion term has been employed to determine the solute−surface, solvent−surface, and additive−surface interfaces. The adsorption energies of different molecular auxiliaries in various step configurations on oxygen-rich {01̅ 1̅ } and hydrogen-rich {011} faces have been determined to examine different adsorption pathways before obtaining the rate of growth. Considering that crystallization is a thermally activated process that involves the kinetic and thermodynamic aspects of the adsorption of different molecular auxiliaries at the interface, the rate of growth along the opposite ends of the polar axis has been calculated to determine growth anisotropy. We have constructed eight different step configurations (¢ 1 −¢ 8 ) on the (011) and (01̅ 1̅ ) faces to determine the adsorption pathways of the resorcinol molecule. It has been found that the adsorption of different auxiliaries in ¢ 1 , ¢ 4 , and ¢ 1 step configurations would determine the growth rate of oxygen-rich faces from aqueous, acetic acid, and acetone solutions, respectively. Our results show that the oxygen-rich faces grew 9 and 6 times faster than the hydrogen-rich faces from aqueous and acetone solutions, respectively. However, the growth rate of the oxygen-rich faces is nearly 3 orders of magnitude lower than that of the hydrogen-rich faces during acetic acid-mediated crystallization. Our study suggests that the solvent adsorption energy toward the oxygen-rich faces is not strong enough to explain the experimentally observed growth disruption of the oxygen-rich faces from acetic acid solution. We find that the strongly adsorbed acetic acid on the oxygen-rich faces rotates one of the hydroxyl groups of the surface molecule from anti to the syn position, which causes an appreciable delay in their growth. Moreover, adsorption of different auxiliaries in the ¢ 6 step configuration would determine the growth rate of hydrogen-rich faces from aqueous, acetic acid, and acetone solutions. The adsorption energies of water, acetic acid, acetone, and different conformers/tailor-made additives in various step configurations have also been evaluated to determine the effect of these auxiliaries on the unidirectional growth along the polar axis. Our results show that the asymmetry in growth decreases with increasing saturation temperatures and supersaturation, which is consistent with the experimental results. Increased concentrations of βand γphase conformers of resorcinol and orcinol lead to increased asymmetry from aqueous growth. However, asymmetry from aqueous growth decreases with in...

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Controlling the aqueous growth of urea crystals with different growth inhibitors: a molecular-scale study

Abstract: Effect of different growth additives on the aqueous growth of crystalline urea is investigated computationally at the different levels of supersaturation and additive concentration.

Cited by 7 publications

References 101 publications

Crystal Growth of Urea and Its Modulation by Additives as Analyzed by All-Atom MD Simulation and Solution Theory

Crystal Growth of Urea and Its Modulation by Additives as Analyzed by All-Atom MD Simulation and Solution Theory

Morphology Regulation of Organophosphate Crystals by Micro‐Jetting Technique

Role of Different Solvents and Tailor-Made Additives in Asymmetry in Growth Rates along the Opposite Ends of the Polar Axis: The Riddle of α-Resorcinol

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