Structure of Molecularly -Thin Perfluoropolyether Films on Amorphous Carbon Surfaces

1998 ◽  
Vol 517 ◽  
Author(s):  
G.W. Tyndall ◽  
R.J. Waltman
Keyword(s):  
Surface Energy ◽  
Amorphous Carbon ◽  
Polymer Films ◽  
Energy Data ◽  
Surface Energies ◽  
Carbon Surfaces ◽  
Adhesive Interactions ◽  
Perfluoropolyether Films ◽  
Underlying Substrate

AbstractSurface energies of molecularly-thin, perfluoropolyether (PFPE)-lubricated, amorphous carbon surfaces are presented as a function of the applied PFPE structure and thickness. A framework is developed to aid in the interpretation of the surface energy data. Information regarding the structure of these PFPE films adsorbed on CHx at the monolayer thickness levels is elucidated. Evidence for ordering in these polymer films is presented and interpreted to result from a combination of both, lateral cohesive interactions within the plane of the monolayer, and adhesive interactions between the PFPE monolayer and the underlying substrate.

scholarly journals Vertical Orientation of Liquid Crystal on 4-n-Alkyloxyphenoxymethyl-Substituted Polystyrene Containing Liquid Crystal Precursor

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 736
Author(s):  
Kyutae Seo ◽  
Hyo Kang
Keyword(s):  
Molecular Structure ◽  
Liquid Crystal ◽  
Surface Energy ◽  
Polymer Films ◽  
Ultraviolet Irradiation ◽  
Molar Fraction ◽  
Side Chain ◽  
Polymer Modification ◽  
Vertical Orientation ◽  
Surface Energies

We synthesized a series of polystyrene derivatives that were modified with precursors of liquid crystal (LC) molecules, such as 4-ethyloxyphenol (homopolymer PEOP and copolymer PEOP#; # = 20, 40, 60, and 80, where # indicates the molar fraction of 4-ethyloxyphenoxymethyl in the side chain), 4-n-butyloxyphenol (PBOP), 4-n-hexyloxyphenol (PHOP), and 4-n-octyloxyphenol (POOP), via polymer modification reaction to investigate the orientation of LC molecules on polymer films, exhibiting part of the LC molecular structure. LC molecules showed a stable and uniform vertical orientation in LC cells fabricated with polymers that have 4-ethyloxyphenoxymethyl in the range of 40–100 mol%. In addition, similar results were obtained in LC cells fabricated with homopolymers of PEOP, PBOP, PHOP, and POOP. The vertical orientation of LC molecules in LC cells fabricated with polymer films correlated to the surface energy of polymer films. For example, vertical LC orientation was observed when the total surface energies of the polymer films were lower than approximately 43.2 mJ/m2. Good alignment stabilities were observed at 150 °C and 20 J/cm2 of ultraviolet irradiation for LC cells fabricated with PEOP film.

The Molecular Spreading of Nonpolar Perfluoropolyether Films on Amorphous Carbon Surfaces

2000 ◽  
Vol 228 (2) ◽  
pp. 405-409 ◽  
Author(s):  
Min C. Kim ◽  
David M. Phillips ◽  
Xiaoding Ma ◽  
Myung S. Jhon
Keyword(s):  
Amorphous Carbon ◽  
Carbon Surfaces ◽  
Perfluoropolyether Films

Surface energy and hybridization studies of amorphous carbon surfaces

2008 ◽  
Vol 254 (16) ◽  
pp. 4980-4991 ◽  
Author(s):  
A. Zebda ◽  
H. Sabbah ◽  
S. Ababou-Girard ◽  
F. Solal ◽  
C. Godet
Keyword(s):  
Surface Energy ◽  
Amorphous Carbon ◽  
Carbon Surfaces

SURFACE ENERGY ENGINEERING OF Cu SURFACE BY STRAIN: FIRST-PRINCIPLES CALCULATIONS

2013 ◽  
Vol 20 (06) ◽  
pp. 1350054 ◽  
Author(s):  
L. HE ◽  
Y. W. LIU ◽  
W. J. TONG ◽  
J. G. LIN ◽  
X. F. WANG
Keyword(s):  
Surface Energy ◽  
First Principles ◽  
Strain Distribution ◽  
First Principles Calculations ◽  
Surface Energies ◽  
Energy Engineering

Surface energies of strained Cu surfaces were studied systematically using first-principles methods. Results showed that the strain-stabilization of Cu surface was anisotropic and strongly related to the strain distribution. This strain-induced approach could be used as an effective way to engineer the surface energies of metals.

scholarly journals Surface energies emerging in a microscopic, two-dimensional two-well problem

2017 ◽  
Vol 147 (5) ◽  
pp. 1041-1089 ◽  
Author(s):  
Georgy Kitavtsev ◽  
Stephan Luckhaus ◽  
Angkana Rüland
Keyword(s):  
Surface Energy ◽  
Two Dimensional ◽  
Direct Control ◽  
First Order ◽  
Surface Energies ◽  
Energy Scaling ◽  
Continuous Analogue ◽  
Dimensional Shape ◽  
Set Up ◽  
Microscopic Modelling

In this paper we are interested in the microscopic modelling of a two-dimensional two-well problem that arises from the square-to-rectangular transformation in (two-dimensional) shape-memory materials. In this discrete set-up, we focus on the surface energy scaling regime and further analyse the Hamiltonian that was introduced by Kitavtsev et al. in 2015. It turns out that this class of Hamiltonians allows for a direct control of the discrete second-order gradients and for a one-sided comparison with a two-dimensional spin system. Using this and relying on the ideas of Conti and Schweizer, which were developed for a continuous analogue of the model under consideration, we derive a (first-order) continuum limit. This shows the emergence of surface energy in the form of a sharp-interface limiting model as well the explicit structure of the minimizers to the latter.

scholarly journals A note on the effect of surface topography on adhesion of hard elastic rough bodies with low surface energy

2019 ◽  
Vol 28 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Guido Violano ◽  
Giuseppe Demelio ◽  
Luciano Afferrante
Keyword(s):  
Surface Roughness ◽  
Surface Energy ◽  
Adhesive Contact ◽  
Low Surface Energy ◽  
Surface Gradient ◽  
Self Consistent ◽  
Remarkable Result ◽  
Roughness Amplitude ◽  
Adhesive Interactions ◽  
Effect Of Surface

AbstractAdhesion between bodies is strongly influenced by surface roughness. In this note, we try to clarify how the statistical properties of the contacting surfaces affect the adhesion under the assumption of long-range adhesive interactions.Specifically, we show that the adhesive interactions are influenced only by the roughness amplitude hrms, while the rms surface gradient h0rmsonly affects the non-adhesive contact force. This is a remarkable result if one takes into account the intrinsic difficulty in defining $h_{\mathrm{rms}}^{^{\prime }}.$Results are also corroborated by a comparison with self-consistent numerical calculations.

Optimization of fluid characteristics of 2D materials for inkjet printing

MRS Advances ◽  
2016 ◽  
Vol 1 (30) ◽  
pp. 2199-2206 ◽  
Author(s):  
Monica Michel ◽  
Jay A. Desai ◽  
Alberto Delgado ◽  
Chandan Biswas ◽  
Anupama B. Kaul
Keyword(s):  
Surface Energy ◽  
Inkjet Printing ◽  
Ethyl Cellulose ◽  
2D Materials ◽  
The Novel ◽  
Liquid Exfoliation ◽  
Drop Dynamics ◽  
Surface Energies ◽  
Fluid Characteristics

ABSTRACT2D materials have shown to be the next step in semiconductor use and device manufacturing that can allow us to reduce the size of most electronics. One of the novel ways to obtain 2D materials is through liquid exfoliation, in which these materials can be obtained by dispersing the smallest possible particles in different solvents. Once obtained, the solutions can be used to manufacture devices via different processes, one of which is inkjet printing. This process relies in selecting “jettable” fluids, which need to have the necessary combination of viscosity and surface energy or “wettability”. In this work we have modified the viscosities and surface energies of five solvents: IPA (Isopropanol), NMP (N-methyl – 2 pyrrolidone), DMA (Dimethylacetamide), DMF (Dimethylformamide) and a mixture of Cyclohexanone / Terpineol 7:3. We have found an avenue to tailor the viscosity of these solvents though the addition of Ethyl Cellulose (EC), where the viscosity has been increased by up to 15 times at an EC concentration of 6%. For inkjet printing, ideally a viscosity of 4 – 10 cP is recommended, which we have been able to achieve with all of the solvents studied. It has been found that the different solvents present different susceptibilities to the EC addition, with DMA and DMF being the least sensitive to the EC addition. We have also studied the change in the drop dynamics and interactions of the 2D solutions with the substrate. Through this analysis we have found solvents that appear to be attractive for inkjet printing of MoS2 and graphite.

Use of Contact Angle Hysteresis in Estimating Thin Polymer Film Surface Energy and Wettability

2006 ◽  
Author(s):  
I. S. Bayer ◽  
C. M. Megaridis ◽  
J. Zhang ◽  
D. Gamota
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Surface Energy ◽  
Uv Radiation ◽  
Contact Angle Hysteresis ◽  
Estimation Methods ◽  
Thin Polymer Film ◽  
Energy Estimation ◽  
Surface Energies ◽  
Polar Probe

A recent surface energy estimation method [1] interpreting contact angle hysteresis measurements was used to estimate surface energy of various commercially important polymer films including UV radiation cross-linked acrylic based monomer systems. The validity of the method was tested on highly hydrophobic non-polar amorphous fluoro-polymers using a number of polar and low surface tension liquids. Contact angle hysteresis was present on these surfaces even though surface morphology of the solution processed fluoro-polymers is close to ideal. Estimated surface energies using such probe liquids were consistent varying slightly with the probe liquid type. On such highly ordered and non-polar polymer surfaces use of polar and low surface tension liquids results in accurate surface energy estimation. However, use of polar probe liquids commonly employed in surface energy estimation methods, such as, Harmonic mean (HM), Geometric mean (GM) or Lewis Acid-Base method (LWAB) on polar surfaces such as polyester resulted in inconsistent surface energy values. To strengthen this observation, the ASTM surface energy estimation procedure (ASTM D2578 04a) developed for polyethylene and polypropylene surfaces (both non-polar) was employed on a sample polar polyester surface using the ASTM probe liquids. Results showed inconsistent surface energy values supporting the conclusion that care must be exercised during use of polar probe liquids in estimating surface energy on polar polymers with the contact angle hysteresis method. Finally, UV radiation cross-linkable acrylic polymer surface energies were estimated with the hysteresis method. Surface energy results were consistent based on five different probe liquids. It was observed that surface energy of the cross-linked monomer networks decreased slightly with increasing UV curing time.

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