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Title: Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment

Authors:
ORCiD logo; ; ; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1368417
Grant/Contract Number:
AC05-76RL01830
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Related Information: CHORUS Timestamp: 2017-08-08 10:29:16; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English

Citation Formats

Li, Dongsheng, Chun, Jaehun, Xiao, Dongdong, Zhou, Weijiang, Cai, Huacheng, Zhang, Lei, Rosso, Kevin M., Mundy, Christopher J., Schenter, Gregory K., and De Yoreo, James J.. Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment. United States: N. p., 2017. Web. doi:10.1073/pnas.1621186114.
Li, Dongsheng, Chun, Jaehun, Xiao, Dongdong, Zhou, Weijiang, Cai, Huacheng, Zhang, Lei, Rosso, Kevin M., Mundy, Christopher J., Schenter, Gregory K., & De Yoreo, James J.. Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment. United States. doi:10.1073/pnas.1621186114.
Li, Dongsheng, Chun, Jaehun, Xiao, Dongdong, Zhou, Weijiang, Cai, Huacheng, Zhang, Lei, Rosso, Kevin M., Mundy, Christopher J., Schenter, Gregory K., and De Yoreo, James J.. 2017. "Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment". United States. doi:10.1073/pnas.1621186114.
@article{osti_1368417,
title = {Trends in mica–mica adhesion reflect the influence of molecular details on long-range dispersion forces underlying aggregation and coalignment},
author = {Li, Dongsheng and Chun, Jaehun and Xiao, Dongdong and Zhou, Weijiang and Cai, Huacheng and Zhang, Lei and Rosso, Kevin M. and Mundy, Christopher J. and Schenter, Gregory K. and De Yoreo, James J.},
abstractNote = {},
doi = {10.1073/pnas.1621186114},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 7
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1621186114

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  • Oriented attachment of nanocrystalline subunits is recognized as a common crystallization pathway that is closely related to formation of nanoparticle superlattices, mesocrystals, and other kinetically stabilized structures. Approaching particles have been observed to rotate to achieve co-alignment while separated by nanometer-scale solvent layers. Little is known about the forces that drive co-alignment, particularly in this “solvent-separated” regime. To obtain a mechanistic understanding of this process, we used atomic force microscopy-based dynamic force spectroscopy with tips fabricated from oriented mica to measure the adhesion forces between mica (001) surfaces in electrolyte solutions as a function of orientation, temperature, electrolyte type, andmore » electrolyte concentration. The results reveal a ~60° periodicity as well as a complex dependence on electrolyte concentration and temperature. A continuum model that considers the competition between electrostatic repulsion and van der Waals attraction, augmented by microscopic details that include surface separation, water structure, ion hydration, and charge regulation at the interface, qualitatively reproduces the observed trends and implies that dispersion forces are responsible for establishing co-alignment in the solvent-separated state.« less
  • Hydrophobic forces were measured using a Mark IV surface force apparatus with mica surfaces in equilibrium with dodecylamine hydrochloride (DAHCl) solutions at pH 5.7. With DAHCl alone, only short-range hydrophobic forces were observed with decay lengths of 1.3 nm. In the presence of dodecanol, long-range hydrophobic forces were observed with the decay length as large as 9.0 nm, which represents the strongest ever recorded hydrophobic force with soluble single-chain surfactants. The appearance of the long-range hydrophobic forces in the presence of neutral surfactants can be attributed to the coadsorption mechanism, by which a close-packed mixed monolayer of dodecylammonium ions andmore » dodecanol is formed on the mica surface. The decay lengths of the hydrophobic forces obtained in the present work and reported in the literature have been plotted vs advancing water contact angles ({theta}{sub a}). The results show that long-range hydrophobic forces appear at {theta}{sub a} {>=} 90{degree}, which may be attributed to the formation of domains of close-packed hydrocarbon chains. These domains may have large dipole moments (or charges), which correlate with those of the opposing surface to give rise to long-range hydrophobic forces. The domains may also serve as sites for microscopic cavitation, as the local contact angle may exceed 90{degree} and thereby satisfy the thermodynamic requirement for cavitation.« less
  • A Mark IV surface force apparatus was used to measure forces between mica surfaces in dodecylamine hydrochloride (DAHCl) solutions. At pH 5.7, only short-range hydrophobic forces with decay lengths of approximately 1.3 nm were observed. At pH 9.5, however, a long-range hydrophobic force with a decay length of 5.5 nm was observed due to the coadsorption of dodecylammonium ions and dodecylamine, which increases the packing density of hydrocarbon chains on the mica surface. At pH 10.1, no significant hydrophobic forces are observed above 2 {times} 10{sup {minus}5} M DAHCl possibly due to the formation of phase-separated amine on the surface.more » This concentration is 50 times below that of bulk precipitation. Furthermore, the force curves obtained at pH 10.1 exhibit repulsive steric forces at separation distances below 30 nm, which may provide evidence for the existence of preprecipitation complexes on the surface. The pH at which the long-range hydrophobic force appears corresponds to the pH where the flotation of quartz reaches a maximum, suggesting that long-range hydrophobic forces may be required for good flotation.« less
  • Using a Mark IV surface force apparatus, adsorption of dodecylamine hydrochloride has been studied at pH 5.7 in the presence and absence of octanol. With amine alone, the repulsive forces between mica surfaces are reduced due to charge neutralization and attractive hydrophobic force; however, the latter is of relatively short range with decay lengths in the range of 1.2--1.4 nm. In the presence of amine and octanol, long-range hydrophobic forces are observed, the largest decay length being 6.8 nm. The appearance of the long-range hydrophobic force in the presence of octanol may be attributed to the coadsorption of the neutralmore » surfactant in the monolayer of dodecylammonium ions on mica. The increased hydrophobic force due to the coadsorption of octanol is also manifested by the improved floatability of silica in dodecylamine solutions.« less