How does temperature modulate the structural properties of aggregated melamine in aqueous solution-An answer from...

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• Melamine's aggregation in aqueous solutions is crucial for its material properties.
• Understanding temperature-dependent aggregation is key to controlling melamine's behavior.

Purpose of the Study:

• To investigate the molecular mechanisms of melamine aggregation in water.
• To determine the effect of temperature on melamine's aggregated structure and stability.

Main Methods:

• Classical molecular dynamics simulations of eight melamine molecules in water from 300 K to 380 K.
• Analysis of hydrogen bonding, preferential interaction parameter, orientational probability, and π-π stacking.
• Dynamical calculations including cluster analysis and autocorrelation functions.
• Thermodynamic analysis using free energy of solvation, association constant, and binding free energy.
• Potential of mean force calculations with umbrella sampling.

Main Results:

• Hydrogen bonds between sp3 N-sp2 N atoms are the primary drivers of melamine aggregation and are weakened by increasing temperature.
• Higher temperatures lead to destabilization of aggregated melamine in water.
• Temperature has a negligible impact on the orientational probability between triazine cores.
• π-π stacking interactions play a minor role in melamine aggregation.
• Increased temperature reduces the probability of higher-order cluster formation.

Conclusions:

• Temperature significantly influences melamine aggregation in water primarily by disrupting key hydrogen bonds.
• Elevated temperatures promote the dissociation of melamine aggregates, impacting solubility and material formation.
• The findings provide thermodynamic and dynamic insights into temperature-controlled melamine aggregation.