Energetic analysis of succinic acid in water droplets: insight into the size-dependent solubility of atmospheric nanoparticles

<p>Size-dependent solubility is prevalent in atmospheric nanoparticles, but a molecular level understanding is still insufficient, especially for organic compounds. Here, we performed molecular dynamics simulations to investigate the size dependence of succinic acid solvation on the scale of ~1-4 nm with the potential of mean forces method. Our analyses reveal that the surface preference of succinic acid is stronger for a droplet than the slab of the same size, and the surface propensity is enhanced due to the curvature effect as the droplet becomes smaller. Energetic analyses show that such surface preference is primarily an enthalpic effect in both systems, while the entropic effect further enhances the surface propensity in droplets. On the other hand, with decreasing droplet size, the solubility of succinic acid in the internal bulk volume may decrease, imposing an opposite effect on the size dependence of solubility as compared with the enhanced surface propensity. Meanwhile, structural analyses, however, show that the surface to internal bulk volume ratio increases drastically, especially when considering the surface in respect to succinic acid, e.g., for droplet with radius of 1 nm, the internal bulk volume would be already close to zero for the succinic acid molecule.</p>

Energetic analysis of succinic acid in water droplets: insight into the size-dependent solubility of atmospheric nanoparticles

Size-dependent solubility is prevalent in atmospheric nanoparticles, but a molecular level understanding is still insufficient, especially for organic compounds. Here, we performed molecular dynamics simulations to investigate the size dependence of succinic acid solvation on the scale of ~1–4 nm with the potential of mean forces method. Our analyses reveal that the surface preference of succinic acid is stronger for a droplet than the slab of the same size, and the surface propensity is enhanced due to the curvature effect as the droplet becomes smaller. Energetic analyses show that such surface preference is primarily an enthalpic effect in both systems, while the entropic effect further enhances the surface propensity in droplets. On the other hand, with decreasing droplet size, the solubility of succinic acid in the internal bulk volume may decrease, imposing an opposite effect on the size dependence of solubility as compared with the enhanced surface propensity. Meanwhile, structural analyses, however, show that the surface to internal bulk volume ratio increases drastically, especially when considering the surface in respect to succinic acid, e.g., for droplet with radius of 1 nm, the internal bulk volume would be already close to zero for the succinic acid molecule.

Preferred penetration of active nano-rods into narrow channels and their clustering

In a channel connected to a reservoir, passive particles prefer staying in the reservoir than the channel due to entropic effect, as the size of particles is comparable to that...

When the Wells Run Dry: Reimagining Azerbaijan’s Post-Oil Futures

Azerbaijan is a case study of the issue of nations with non-renewable natural resource-based economies, usually fossil fuels, facing depletion of what was deemed to be their principal resource. Azerbaijan’s petroleum wealth has been a defining feature of its national economy, social development, and national character for 150 years. It has also manifested what is commonly known as the “resource curse” for its entropic effect on all of the other sectors of the economy. This main driver of its economy is projected to be exhausted roughly within the next 30 years. The focus of this piece is on assessing the prospects of developing a national economy that can create a more equitable and sustainable economic public benefit over the next generation. Each of the pathways summarized herein are from capstone project research reports of graduate students on this issue. It is ultimately intended to be a demonstration of conducting applied future-oriented anticipatory action learning.

Entropic effect and residue specific entropic contribution to the cooperativity in streptavidin–biotin binding

Molecular dynamics (MD) simulations were performed employing the polarized protein-specific charge (PPC) to explore the origin of the cooperativity in streptavidin–biotin systems (wild type, two single mutations and one double-mutation).

Understanding the entropic effect in chorismate mutase reaction catalyzed by isochorismate-pyruvate lyase fromPseudomonas aeruginosa(PchB)

The substrate preorganization process in the entropically driven PchB-catalyzed chorismate mutase reaction leads to a remarkable apparent entropic effect.