scholarly journals Towards a standardized setup for surface energy calculations

2017 ◽  
Vol 95 (8) ◽  
Author(s):  
Jakub W. Kaminski ◽  
Peter Kratzer ◽  
Christian Ratsch
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.


Author(s):  
Jayaramulu Kolleboyina ◽  
HANEESH SAINI ◽  
Parashuram Kallem ◽  
Eva Otyepková ◽  
Florian Geyer ◽  
...  

Superhydrophobic MOF-nanosheets assembled on the outside of an aqueous droplet form ‘liquid marbles’. A facile mechanochemical-based synthesis followed by ultrasonication was used to prepare two-dimensional superhydrophobic-oleophilic MOF nanosheets of a...


2015 ◽  
Vol 12 (108) ◽  
pp. 20150464 ◽  
Author(s):  
Alyssa Y. Stark ◽  
Daniel M. Dryden ◽  
Jeffrey Olderman ◽  
Kelly A. Peterson ◽  
Peter H. Niewiarowski ◽  
...  

Fluorinated substrates like Teflon ® (poly(tetrafluoroethylene); PTFE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on PTFE. Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor–Winterton approximation and the Young–Dupré equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air.


2015 ◽  
Vol 106 (21) ◽  
pp. 212103 ◽  
Author(s):  
C. E. Dreyer ◽  
A. Janotti ◽  
C. G. Van de Walle

Author(s):  
H. P. Beck ◽  
T. Beyer

AbstractSome applications of surface potential and MAPSE (Madelung Part of Surface Energy) calculations are presented. MAPSE is a useful tool for the prediction of crystal morphologies and the terminating ion layer in crystal, surfaces. The surface specific part of a lattice potential, called epi-potential can be used to analyse the range of surface effects and to study the potential topology in epi-potential maps. These maps of crystal surfaces show the positions of the next one or two missing ion layers above the surface as active centres for reactions and adsorption phenomena.We present here calculations for NaCl, CaF


2010 ◽  
Vol 87 (6) ◽  
pp. 608-612 ◽  
Author(s):  
James G. Eberhart ◽  
Steve Horner

1977 ◽  
Vol 15 (2) ◽  
pp. 580-583 ◽  
Author(s):  
Mark Rasolt ◽  
J. Shy-Yih Wang ◽  
L. M. Kahn

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