A novel method for measuring the surface tension of free standing smectic films

2002 ◽  
Vol 73 (1) ◽  
pp. 114-118 ◽  
Author(s):  
F. Schneider
Keyword(s):  
Surface Tension ◽  
Free Standing ◽  
Novel Method

On-Chip Fabrication of None-Dead-Volume Microtips for ESI-MS Applications

2007 ◽  
Vol 121-123 ◽  
pp. 611-614
Author(s):  
Che Hsin Lin ◽  
Jen Taie Shiea ◽  
Yen Lieng Lin
Keyword(s):  
Surface Tension ◽  
Low Cost ◽  
Microfluidic Channel ◽  
Dead Volume ◽  
Esi Ms ◽  
Rapid Fabrication ◽  
Chip Fabrication ◽  
Novel Method ◽  
On Chip ◽  
Highly Uniform

This paper proposes a novel method to on-chip fabricate a none-dead-volume microtip for ESI-MS applications. The microfluidic chip and ESI tip are fabricated in low-cost plastic based materials using a simple and rapid fabrication process. A constant-speed-pulling method is developed to fabricate the ESI tip by pulling mixed PMMA glue using a 30-μm stainless wire through the pre-formed microfluidic channel. The equilibrium of surface tension of PMMA glue will result in a sharp tip after curing. A highly uniform micro-tip can be formed directly at the outlet of the microfluidic channel with minimum dead-volume zone. Detection of caffeine, myoglobin, lysozyme and cytochrome C biosamples confirms the microchip device can be used for high resolution ESI-MS applications.

Improvement of the Seebeck coefficient of PEDOT:PSS by chemical reduction combined with a novel method for its transfer using free-standing thin films

2014 ◽  
Vol 2 (7) ◽  
pp. 1278-1283 ◽  
Author(s):  
Nicolas Massonnet ◽  
Alexandre Carella ◽  
Olivier Jaudouin ◽  
Patrice Rannou ◽  
Gautier Laval ◽  
...  
Keyword(s):  
Thin Films ◽  
Seebeck Coefficient ◽  
Chemical Reduction ◽  
Free Standing ◽  
Novel Method

scholarly journals Interface Characteristics of Neat Melts and Binary Mixtures of Polyethylenes from Atomistic Molecular Dynamics Simulations

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1059
Author(s):  
Sanghun Lee ◽  
Curtis W. Frank ◽  
Do Y. Yoon
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Molecular Dynamics Simulations ◽  
Binary Mixtures ◽  
Surface Segregation ◽  
Surface Region ◽  
Polymer Chains ◽  
Methyl Groups ◽  
Free Standing ◽  
Dynamics Simulations

Molecular dynamics simulations of free-standing thin films of neat melts of polyethylene (PE) chains up to C150H302 and their binary mixtures with n-C13H28 are performed employing a united atom model. We estimate the surface tension values of PE melts from the atomic virial tensor over a range of temperatures, which are in good agreement with experimental results. Compared with short n-alkane systems, there is an enhanced surface segregation of methyl chain ends in longer PE chains. Moreover, the methyl groups become more segregated in the surface region with decreasing temperature, leading to the conclusion that the surface-segregation of methyl chain ends mainly arises from the enthalpic origin attributed to the lower cohesive energy density of terminal methyl groups. In the mixtures of two different chain lengths, the shorter chains are more likely to be found in the surface region, and this molecular segregation in moderately asymmetric mixtures in the chain length (C13H28 + C44H90) is dominated by the enthalpic effect of methyl chain ends. Such molecular segregation is further enhanced and dominated by the entropic effect of conformational constraints in the surface for the highly asymmetric mixtures containing long polymer chains (C13H28 + C150H3020). The estimated surface tension values of the mixtures are consistent with the observed molecular segregation characteristics. Despite this molecular segregation, the normalized density of methyl chain ends of the longer chain is more strongly enhanced, as compared with the all-segment density of the longer chain itself, in the surface region of melt mixtures. In addition, the molecular segregation results in higher order parameter of the shorter-chain segments at the surface and deeper persistence of surface-induced segmental order into the film for the longer chains, as compared with those in neat melt films.

Surface tension of free-standing liquid-crystal films

1994 ◽  
Vol 49 (5) ◽  
pp. R3587-R3590 ◽  
Author(s):  
T. Stoebe ◽  
P. Mach ◽  
C. C. Huang
Keyword(s):  
Surface Tension ◽  
Liquid Crystal ◽  
Free Standing ◽  
Liquid Crystal Films ◽  
Crystal Films

A novel method for preventing collapse of air-dried specimens for heavy metal shadowing

1986 ◽  
Vol 44 ◽  
pp. 228-229
Author(s):  
M. Kessel ◽  
E. L. Buhle ◽  
E. Glavaris ◽  
U. Aebi
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Surface Tension ◽  
Freeze Drying ◽  
Three Dimensional ◽  
Biological Molecules ◽  
Air Drying ◽  
Critical Step ◽  
Novel Method ◽  
Thermal Vibrations

Heavy metal shadowing is one of the oldest and most useful methods of enhancing the contrast of biological molecules for visualization by electron microscopy. A critical step in this method is the dehydration of the specimen prior to metal shadowing without causing distortion and collapse of the structure and consequent loss of the three-dimensional information. Two methods commonly employed today are glycerol spraying/vaccuum evaporation and freeze-drying. While glycerol spraying is the easier method of the two, it does not significantly prevent collapse artifact during air-drying and thus is limited to single extended molecules. Freeze-drying minimizes the collapse artifact of flattening and distortion due to surface tension. Freeze-drying preparations suffer their own problems of thermal vibrations and possible contamination by a eutectic of remaining salts and proteins.

scholarly journals DISLOCATIONS IN UNIAXIAL LAMELLAR PHASES OF LIQUID CRYSTALS, POLYMERS AND AMPHIPHILIC SYSTEMS

1995 ◽  
Vol 09 (13n14) ◽  
pp. 1515-1573 ◽  
Author(s):  
ROBERT HOŁYST ◽  
PATRICK OSWALD
Keyword(s):  
Surface Tension ◽  
Liquid Crystals ◽  
Elastic Constant ◽  
Finite System ◽  
Ternary Mixtures ◽  
Free Standing ◽  
Screw Dislocations ◽  
Elastic Interactions ◽  
Lamellar Phases ◽  
Edge Dislocations

Dislocations in soft condensed matter systems such as lamellar systems of polymers, liquid crystals and ternary mixtures of oil, water and surfactant (amphiphilic systems) are described in the framework of continuum elastic theory. These systems are the subject of studies of physics, chemistry and biology. They also find applications in industry. Here we will discuss in detail the influence of dislocations on the bulk and surface properties of these lamellar phases. Especially the latter properties have only been recently studied in detail. We will present the experimental evidence of the existence of screw and edge dislocations in the systems and study their static properties such as: energy, line tension and core structure. Next we will show how the surface influences the equilibrium position of dislocations in the system. We will give the theoretical predictions and present the experimental results on thin copolymer films, free standing films of liquid crystals and smectic droplets shapes. In semi-infinite lamellar systems characterized by small surface tension the dislocation is stabilized at a finite distance, heq, from the surface, due to the surface bending elastic constant, Ks (for zero surface tension heq≈Ks/2K, where K is the bulk bending elastic constant). For large surface tension the edge dislocations are strongly repelled by the surface and the equilibrium location for finite symmetric systems such as free standing liquid crystal films shifts towards the center of the system. The surface is deformed by dislocations. These deformations are known as edge profiles. They will be discussed for finite systems with small and large surface tension. Surface deformations induce elastic interactions between edge dislocations, which decay exponentially with distance with decay length proportional to [Formula: see text] where D is the size of the system normal to lamellas. Two screw dislocations in finite system interact with the logarithmic potential, which is proportional to the surface tension and inversly proportional to D. The surface induced elastic interactions will be compared to, well-known, bulk deformation induced interactions. A new phenonenon discussed in our paper is the fluctuations induced interactions between edge dislocations, which follows from the Helfrich mechanism for flexible objects. At suitable conditions, edge dislocations can undergo an unbinding transition. Also a single dislocation loop can undergo an unbinding transition. We will calculate the properties of the loop inside finite system and discuss in particular the unbinding transition in freely suspended smectic films. We shall also compute the equilibrium size of the loop contained between two hard walls. Finally we will discuss the dynamical bulk properties of dislocations such as: mobility (climb and glide), permeation, and helical instability of screw dislocations. Lubrication theory will also be discussed.

scholarly journals Effects of surface tension on the size-dependent ferroelectric characteristics of free-standing BaTiO3 nano-thin films

2011 ◽  
Vol 110 (8) ◽  
pp. 084108 ◽  
Author(s):  
Yu Su ◽  
Haitao Chen ◽  
Jacqueline J. Li ◽  
Ai Kah Soh ◽  
George J. Weng
Keyword(s):  
Thin Films ◽  
Surface Tension ◽  
Free Standing ◽  
Size Dependent
Sign in / Sign up

Export Citation Format

Share Document