Solvation Energy of Ions in Polymers: Effects of Chain Length and Connectivity on Saturated Dipoles near Ions

We illustrate the effects of chain connectivity on the solvation energy of ions immersed in polymer liquids by developing a new coarse-grained molecular dynamics simulation. Our theory accounts for the dielectric response of the polymers through the connection of dipolar, monomeric units with nonlinear springs. In stark contrast to the standard Born solvation energy of ions, our results depend substantially on the chain length of the polymers. We also demonstrate the marked difference in the solvation energies of the ions immersed in non-polymeric particle mixtures, single-component polymers, polymer blends, and block copolymers. Thus, we suggest that the chain architecture of polymers is a key factor in ion solvation, whereas this feature is often inadequately considered in main theory and simulation literature. Our results are consistent with those predicted by previous coarse-grained mean-field theories when the dipole moment of the polymer compositions is relatively small. However, we also demonstrate that the strong ion–dipole and dipole–dipole interactions cause the chain-like association of the monomeric units, resulting in a qualitative discrepancy between the mean-field theory and simulation. Such a strong electrostatic correlation may reverse the dependence of the chain length on the solvation energy of the ions in the polymers

Predicted land demand area in the oasis under three scenarios from 2009 to 2018 (units: km²).

<p>Predicted land demand area in the oasis under three scenarios from 2009 to 2018 (units: km²).</p

Oasis carbon storage based on InVEST and land-use change in 2000, 2009, S1, S2, and S3.

<p>Oasis carbon storage based on InVEST and land-use change in 2000, 2009, S1, S2, and S3.</p

Location of Zhangye oasis.

<p>Location of Zhangye oasis.</p

Facile Fabrication of a Superhydrophobic Cu Surface via a Selective Etching of High-Energy Facets

The Cu surface with a dual-scale roughness has been prepared via a facile solution-phase etching route by the H₂O₂/HCl etchants. The selective etching of the high-energy {110} facets occurs at an ultralow rate of the redox etching reaction. The resultant surface is composed of many polyhedral microprotrusions and nanomastoids on the microprotrusions, exhibiting the binary micro/nanostructures. After hydrophobization, the resultant surface exhibits a water contact angle of 170° and a sliding angle of ∼2.8° for a 5 μL droplet. The combination of the dual-scale roughness and the low surface energy of the adsorbed stearic acid accounts for the superhydrophobicity. Such a superhydrophobic Cu surface has an excellent nonsticking behavior and anticorrosion against electrolyte solution. It also keeps its superhydrophobic ability after a long-time ultrasonication or abrasion test. Our work may shed light on the selective etching of other metal surfaces to create designed dual-scale roughness for superhydrophobicity

Eco-Friendly Fabrication of Superhydrophobic Bayerite Array on Al Foil via an Etching and Growth Process

In this work, we present a clean and atom-economic fabrication of superhydrophobic Al surfaces, where the Al­(III) ions etched off by OH^– can be transformed to a bayerite array growing out of the Al substrate with the help of CO₂ in air. The resultant array is composed of bayerite microneedles with nanosteps on their surfaces, exhibiting binary micro/nanostructures. The formation mechanism of the microneedles follows a fast etching and subsequent kinetic growth route, significantly different from the traditional etching route. After the chemisorption of steric acid, the resultant Al surface shows a water contact angle of 167° and a sliding angle of ∼3° for a 5 μL water droplet. The dual-scale roughness together with the low surface energy of stearic acid accounts for the superhydrophobicity. The resultant Al surface has an anticorrosion against electrolyte solution and robust repellence against acidic or alkali droplets. It also maintains hydrophobicity after ultrasonication treatment

Carbon pools of different land-use types in InVEST (units: MgC•ha⁻¹).

<p>‘<i>Ca</i>’ refers to the aboveground biomass. ‘<i>Cb</i>’ refers to the belowground biomass. ‘<i>Cs</i>’ refers to the soil organic carbon. ‘<i>Cd</i>’ refers to the dead organic matter.</p

Simulations of oasis land use in 2018 under scenarios S1, S2, and S3.

<p>Simulations of oasis land use in 2018 under scenarios S1, S2, and S3.</p

General input and validation data for the SD-CLUE-S model.

<p>General input and validation data for the SD-CLUE-S model.</p

Scenario design based on critical indicators in the study area.

<p>‘S1’ is the historical land-use demand scenario reflecting land demand growth as a continuation of the historical period. ‘S2’ is the moderate protection scenario in which land demand growth was limited by setting critical indicators of economic and social development. ‘S3’ is the strict protection scenario in which land demand growth was simulated with multiple strict protections in the study area.</p