Attractions, Water Structure, and Thermodynamics of Hydrophobic Polymer Collapse

2008 ◽  
Vol 112 (42) ◽  
pp. 13193-13196 ◽  
Author(s):  
Gaurav Goel ◽  
Manoj V. Athawale ◽  
Shekhar Garde ◽  
Thomas M. Truskett
Keyword(s):  
Water Structure ◽  
Polymer Collapse ◽  
Hydrophobic Polymer

scholarly journals Drying-induced hydrophobic polymer collapse

2002 ◽  
Vol 99 (10) ◽  
pp. 6539-6543 ◽  
Author(s):  
P. R. ten Wolde ◽  
D. Chandler
Keyword(s):  
Polymer Collapse ◽  
Hydrophobic Polymer

Molecular origin of urea driven hydrophobic polymer collapse and unfolding depending on side chain chemistry

2017 ◽  
Vol 19 (28) ◽  
pp. 18156-18161 ◽  
Author(s):  
Divya Nayar ◽  
Angelina Folberth ◽  
Nico F. A. van der Vegt
Keyword(s):  
Molecular Simulations ◽  
Side Chain ◽  
Molecular Surfaces ◽  
Polymer Collapse ◽  
Hydrophobic Polymer ◽  
Molecular Origin

Urea ambivalence: molecular simulations show that collapse and unfolding of aqueous polymers occur in response to urea screening of nonpolar molecular surfaces.

Small crowder interactions can drive hydrophobic polymer collapse as well as unfolding

2020 ◽  
Vol 22 (32) ◽  
pp. 18091-18101
Author(s):  
Divya Nayar
Keyword(s):  
Polymer Collapse ◽  
Hydrophobic Polymer

The strength of polymer–crowder attractions determine polymer collapse or unfolding. Collapse may occur via preferential depletion or adsorption of crowders.

Self-avoiding-self-attracting model of polymer collapse and adsorption

1991 ◽  
Vol 1 (3) ◽  
pp. 397-419 ◽  
Author(s):  
S. Cattarinussi ◽  
G. Jug
Keyword(s):  
Polymer Collapse

Currents and water structure north of the Vema Channel

2018 ◽  
Vol 18 (5) ◽  
pp. 1-6 ◽  
Author(s):  
E. G. Morozov ◽  
R. Yu. Tarakanov ◽  
D. I. Frey ◽  
D. G. Borisov
Keyword(s):  
Water Structure

scholarly journals An interplay of excluded-volume and polymer–(co)solvent attractive interactions regulates polymer collapse in mixed solvents

2021 ◽  
Vol 154 (13) ◽  
pp. 134903
Author(s):  
Swaminath Bharadwaj ◽  
Divya Nayar ◽  
Cahit Dalgicdir ◽  
Nico F. A. van der Vegt
Keyword(s):  
Mixed Solvents ◽  
Excluded Volume ◽  
Polymer Collapse

scholarly journals Behavior and properties of water in silicate melts under deep mantle conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bijaya B. Karki ◽  
Dipta B. Ghosh ◽  
Shun-ichiro Karato
Keyword(s):  
Electrical Conductivity ◽  
Molar Volume ◽  
Water Solution ◽  
Pure Water ◽  
Electrical Conductance ◽  
Water Structure ◽  
Bulk Water ◽  
Silicate Melts ◽  
Pressure Regime ◽  
Low Pressures

AbstractWater (H2O) as one of the most abundant fluids present in Earth plays crucial role in the generation and transport of magmas in the interior. Though hydrous silicate melts have been studied extensively, the experimental data are confined to relatively low pressures and the computational results are still rare. Moreover, these studies imply large differences in the way water influences the physical properties of silicate magmas, such as density and electrical conductivity. Here, we investigate the equation of state, speciation, and transport properties of water dissolved in Mg1−xFexSiO3 and Mg2(1−x)Fe2xSiO4 melts (for x = 0 and 0.25) as well as in its bulk (pure) fluid state over the entire mantle pressure regime at 2000–4000 K using first-principles molecular dynamics. The simulation results allow us to constrain the partial molar volume of the water component in melts along with the molar volume of pure water. The predicted volume of silicate melt + water solution is negative at low pressures and becomes almost zero above 15 GPa. Consequently, the hydrous component tends to lower the melt density to similar extent over much of the mantle pressure regime irrespective of composition. Our results also show that hydrogen diffuses fast in silicate melts and enhances the melt electrical conductivity in a way that differs from electrical conduction in the bulk water. The speciation of the water component varies considerably from the bulk water structure as well. Water is dissolved in melts mostly as hydroxyls at low pressure and as –O–H–O–, –O–H–O–H– and other extended species with increasing pressure. On the other hand, the pure water behaves as a molecular fluid below 15 GPa, gradually becoming a dissociated fluid with further compression. On the basis of modeled density and conductivity results, we suggest that partial melts containing a few percent of water may be gravitationally trapped both above and below the upper mantle-transition region. Moreover, such hydrous melts can give rise to detectable electrical conductance by means of electromagnetic sounding observations.

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