Structural Forces in Thin Films Made from Polyelectrolyte Solutions

1997 ◽  
Vol 78 (26) ◽  
pp. 4974-4977 ◽  
Author(s):  
A. Asnacios ◽  
A. Espert ◽  
A. Colin ◽  
D. Langevin
Keyword(s):  
Thin Films ◽  
Structural Forces ◽  
Polyelectrolyte Solutions

Transport Properties of Polyelectrolyte Solutions. Effect of Confinement in Thin Liquid Films

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Jérôme Delacotte ◽  
Dominique Langevin
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Transport Properties ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Conductivity Measurements ◽  
Polyelectrolyte Solutions

AbstractThe role of condensed counterions in transport properties, such as electrical conductivity and viscosity, has been investigated with solutions of a flexible polyelectrolyte. Comparisons with existing theories are proposed. Viscosity is strongly affected by confinement in thin films, depending whether polyelectrolyte chains are adsorbed or not at the film surfaces. The role of counterion mobility is however difficult to assess because the measurements are not accurate enough. It is proposed that this role could be tested by electrical conductivity measurements.

Dependence of Structural Forces in Polyelectrolyte Solutions on Charge Density:  A Combined AFM/SAXS Study

2003 ◽  
Vol 36 (18) ◽  
pp. 6878-6883 ◽  
Author(s):  
Dan Qu ◽  
Damien Baigl ◽  
Claudine E. Williams ◽  
Helmuth Möhwald ◽  
Andreas Fery
Keyword(s):  
Charge Density ◽  
Structural Forces ◽  
Polyelectrolyte Solutions

Electrostatic Self-Assembly of Multilayer Noncentrosymmetric Thin Films and Devices

1999 ◽  
Vol 561 ◽  
Author(s):  
K. M. Lenahan ◽  
T. Zenga ◽  
Y. Liu ◽  
Y.-X. Wang ◽  
W. Zhao ◽  
...  
Keyword(s):  
Thin Films ◽  
Self Assembly ◽  
Dipole Moments ◽  
Low Cost ◽  
Optical Loss ◽  
Deposition Process ◽  
Multilayer Thin Films ◽  
Nonlinear Optical Susceptibility ◽  
Optical Susceptibility ◽  
Polyelectrolyte Solutions

ABSTRACTThe electrostatic self-assembly of multilayer thin films by alternate adsorption from polyelectrolyte solutions spontaneously leads to the formation of noncentrosymmetric structures if the molecules themselves have net dipole moments. Significant second-order nonlinear optical susceptibility has been observed in such films, using both commercially available chromophores and molecules specifically designed to yield an enhanced net dipole moment. Recent results indicate the capability to fabricate piezoelectric films using the same method. The nature of the deposition process results in an alignment of the chromophores that is stable over time and to temperatures up to 150°C, in contrast with poled polymers. ESA films offer the additional major advantages of excellent homogeneity and low optical loss, high thermal and chemical stability, and low cost.

Layer-by-Layer Thin Films of Alginate/Chitosan and Hyaluronic Acid/Chitosan with Tunable Thickness and Surface Roughness

2014 ◽  
Vol 783-786 ◽  
pp. 1226-1231 ◽  
Author(s):  
Thiago Bezerra Taketa ◽  
Marisa Masumi Beppu
Keyword(s):  
Thin Films ◽  
Hyaluronic Acid ◽  
Self Assembly ◽  
Polymer Chains ◽  
Layer By Layer ◽  
Natural Polymers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polyelectrolyte Solutions ◽  
Oppositely Charged

Layer-by-layer (LbL) is a bottom-up technique used for construction of films with self-assembly and self-organizing properties. In most cases, the fundamental driving force for the formation of these films is originated from the electrostatic interaction between oppositely charged species. The charged segments of polyelectrolytes behave as small building units and their orientation and position can be designed to target structures of great complexity. Furthermore, the technique enables the use of various materials, including natural polymers. In this work, we chose the cationic biopolymer chitosan (CHI) and the negative polyelectrolytes sodium alginate (ALG) and hyaluronic acid (HA). The aim of this study was to evaluate the effect of ionic strength (0 versus 200 mM) and pH (3 versus 5) on ALG/CHI and HA/CHI nanostructured multilayered thin films properties. From profilometry and atomic force microscopy (AFM) analyses, changes in thickness and roughness of the coatings were monitored. The presence of salt in polyelectrolyte solutions induced the polymer chains to adopt conformations with more loops and tails and this arrangement in solution was transmitted to films, resulting in rougher surfaces. Furthermore, the film thickness can be precisely controlled by adjusting the pH of the polyelectrolyte solution. The variation of these parameters shows that it is possible to molecularly control chemical and structural properties of nanostructured coatings, thus opening up new possibilities of application (e.g. cell adhesion).

Depletion and Structural Forces in Confined Polyelectrolyte Solutions

Langmuir ◽  
2003 ◽  
Vol 19 (23) ◽  
pp. 9914-9922 ◽  
Author(s):  
Bo Jönsson ◽  
A. Broukhno ◽  
J. Forsman ◽  
T. Åkesson
Keyword(s):  
Structural Forces ◽  
Polyelectrolyte Solutions

MOLECULAR SELF-ASSEMBLY OF SULFONATED POLYANILINE THIN FILMS

2001 ◽  
Vol 08 (05) ◽  
pp. 491-496 ◽  
Author(s):  
W. S. SIM ◽  
F. Y. GOH
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Structural Integrity ◽  
Layer Growth ◽  
Polymer Chains ◽  
Layer By Layer ◽  
Vis Spectroscopy ◽  
Polyelectrolyte Solutions ◽  
Sulfonated Polyaniline

Multilayer polymer thin films with well-defined molecular architectures have been fabricated by an electrostatic self-assembly process involving sequential exposure of glass substrates to polyelectrolyte solutions of sulfonated polyaniline and hexadimethrine bromide. Ultraviolet-Visible (UV-Vis) Spectroscopy indicates layer-by-layer growth of alternating monolayers of oppositely charged polymer chains whose structural integrity is verified by X-ray Photoelectron Spectroscopy (XPS). The surface roughness is measured to be ~3 nm by Atomic Force Microscopy (AFM). The potential applications of these films in optoelectronic devices are discussed.

The study of interfacial reactions of nickel thin films on GaAs

1983 ◽  
Vol 41 ◽  
pp. 156-157
Author(s):  
L.J. Chen ◽  
Y.F. Hsieh
Keyword(s):  
Thin Films ◽  
Integrated Circuits ◽  
Interfacial Reactions ◽  
Metal Contacts ◽  
Nickel Thin Films ◽  
Thin Foils ◽  
The Status ◽  
Si Doped ◽  
Electron Microscopes

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.

Sign in / Sign up

Export Citation Format

Share Document