Positronium Formation as a Probe of Polymer Surfaces and Thin Films

1995 ◽  
Vol 74 (24) ◽  
pp. 4947-4950 ◽  
Author(s):  
L. Xie ◽  
G. B. DeMaggio ◽  
W. E. Frieze ◽  
J. DeVries ◽  
D. W. Gidley ◽  
...  
Keyword(s):  
Thin Films ◽  
Polymer Surfaces ◽  
Positronium Formation

Characterisation of ‘wet’ polymer surfaces for tissue engineering applications: Are flat surfaces a suitable model for complex structures?

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Laleh Safinia ◽  
Jonny J. Blaker ◽  
Véronique Maquet ◽  
Aldo R. Boccaccini ◽  
Athanassios Mantalaris ◽  
...  
Keyword(s):  
Thin Films ◽  
Tissue Engineering ◽  
Pore Wall ◽  
Polymer Surfaces ◽  
Suitable Model ◽  
Tissue Engineering Scaffolds ◽  
3D Structures ◽  
Flat Surfaces ◽  
Point Test ◽  
Highly Porous

AbstractTissue engineering scaffolds are 3D constructs that simulate the growth environment in vivo. The present work aims to address the question of whether thin films, i.e., flat surfaces, are a suitable model for more complex 3D structures? With this in mind a complete study of the morphology and surface chemistry of poly(D,Llactide) (PDLLA) substrates, fabricated into two different structures, is presented. The polymer structures studied include a 3D, porous, foam-like scaffold prepared by the thermally induced phase separation (TIPS) method and flat polymer thin films made by solvent casting. Based on the maximum bubble point test, a new method to assess the wettability of wet pore wall surfaces inside highly porous 3D structures was developed and tested. The maximum pore diameter determined using the maximum bubble point test for the total wetting liquids was confirmed through image analysis of scanning electron micrographs. The method allows the determination of the contact angle between the wet pore wall and a contacting liquid. The captive bubble method was employed to characterise the wettability of flat polymer films in contact with water. Both structures were further characterised using zeta- (ζ-) potential measurements to assess the surface chemistry of the polymer. The results demonstrate that PDLLA contains acidic functional groups and is hydrophobic. In order to evaluate the sensitivity of the test methods, the polymer surfaces were modified by protein adsorption using fibronectin and collagen. ζ-Potential and wettability measurements show that proteins indeed adsorb on virgin PDLLA surfaces. Protein adsorption causes the wettability of the PDLLA for water to improve. Our results strongly indicate that flat surfaces are not a suitable model for surfaces in complex 3D structures such as highly porous tissue engineering scaffolds. Such scaffolds must be characterised as a 3D system.

Novel optical techniques for the analysis of polymer surfaces and thin films

1991 ◽  
Vol 341 (3-4) ◽  
pp. 272-278 ◽  
Author(s):  
W. Knoll ◽  
W. Hickel ◽  
M. Sawodny ◽  
J. Stumpe ◽  
H. Knobloch
Keyword(s):  
Thin Films ◽  
Polymer Surfaces ◽  
Optical Techniques

scholarly journals Thin-film morphologies of block copolymers with nanoparticles

2015 ◽  
Vol 30 (S1) ◽  
pp. S16-S24 ◽  
Author(s):  
Dieter Jehnichen ◽  
Doris Pospiech ◽  
Peter Friedel ◽  
Guping He ◽  
Alessandro Sepe ◽  
...  
Keyword(s):  
Thin Films ◽  
Diblock Copolymers ◽  
Grazing Incidence ◽  
Polymer Surfaces ◽  
Nanostructured Surfaces ◽  
Force Microscopy ◽  
Molar Ratios ◽  
X Ray Scattering ◽  
Atomic Force

Diblock copolymers (BCPs) show phase separation on mesoscopic length scales and form ordered morphologies in both bulk and thin films, the latter resulting in nanostructured surfaces. Morphologies in thin films are strongly influenced by film parameters, the ratio of film thickness and bulk domain spacing. Laterally structured polymer surfaces may serve as templates for controlled assembly of nanoparticles (NPs). We investigated the BCP of poly(n-pentyl methacrylate) and poly(methyl methacrylate) which show bulk morphologies of stacked lamellae or hexagonally packed cylinders. Thin films were investigated by atomic force microscopy and grazing-incidence small-angle X-ray scattering. For film thicknesses f well below dbulk, standing cylinder morphologies were observed in appropriate molar ratios, while film thicknesses around and larger than dbulk resulted in cylinders arranged parallel to surface. To alter and/or improve the morphology also in presence of different NPs (e.g., silica, gold), solvent vapour annealing (SVA) was applied. The BCP morphology usually remains unchanged but periodicities change depending on type and amount of incorporated NPs. It was found that silica clusters enlarge lateral distances of cylinders, whereas Au NPs reduce it. The effect of SVA is weak. The quality of morphology is slightly improved by SVA and lateral distances remain constant or are slightly reduced.

Fundamentals and Advances in the Adhesion of Polymer Surfaces and Thin Films

Langmuir ◽  
2019 ◽  
Vol 35 (48) ◽  
pp. 15914-15936 ◽  
Author(s):  
Lu Gong ◽  
Li Xiang ◽  
Jiawen Zhang ◽  
Jingsi Chen ◽  
Hongbo Zeng
Keyword(s):  
Thin Films ◽  
Polymer Surfaces

Modification of Polymer Surfaces Using Atmospheric Pressure Barrier Discharges

2006 ◽  
Vol 9 (2) ◽  
Author(s):  
Pavel Sťahel ◽  
Vilma Buršíková ◽  
Martin Šíra ◽  
Zdeněk Navrátil ◽  
Petr Kloc ◽  
...  
Keyword(s):  
Thin Films ◽  
Atmospheric Pressure ◽  
Barrier Discharge ◽  
Polymer Surfaces ◽  
Surface Barrier ◽  
Pressure Discharge ◽  
Surface Barrier Discharge ◽  
Board Surface ◽  
Atmospheric Pressure Discharge ◽  
Barrier Discharges

AbstractThe objective of the present work is the development of a technique for the deposition of thin films, by means of an atmospheric pressure discharge, onto a pulp board surface, with the desired surface energy, permeability and wear resistant surface. The deposition of thin films was carried out by a surface barrier discharge at the atmospheric pressure. The films were deposited from mixtures of C

Polymer Surfaces, Interfaces and Thin Films

10.1142/4092 ◽  
2000 ◽  
Author(s):  
Alamgir Karim ◽  
Sanat Kumar
Keyword(s):  
Thin Films ◽  
Polymer Surfaces

On the Robustness of Scratch Testing for Thin Films: the Issue of Tip Geometry for Critical Load Measurement

1999 ◽  
Vol 594 ◽  
Author(s):  
Vincent D. Jardret ◽  
Warren C. Oliver
Keyword(s):  
Thin Films ◽  
Critical Load ◽  
Abrasive Particle ◽  
Great Influence ◽  
Polymer Coatings ◽  
Polymer Surfaces ◽  
Industrial Environment ◽  
Load Measurement ◽  
Abrasion Testing ◽  
Indenter Geometry

AbstractScratch and abrasion resistance of hard protective thin films and polymer coatings is often related to their ability to withstand abrasive conditions without fracturing. Wear particles generate catastrophic and severe wear for hard films, and fractured scratches are often very visible on shiny polymer surfaces. Using a particular abrasive particle shape, the fracture resistance of a surface can be characterized by the load required to create fracture damages. The scratch technique has demonstrated its ability to create these damage mechanisms and characterize the critical load for coatings failure. However, this technique does not yet have the reproducibility and robustness required to be implemented in an industrial environment. The major reason for this lack of robustness is the great influence of the indenter geometry on critical load results and the non-reproducibility of the geometry of conical indenters. This paper addresses this issue and presents a fast and robust method to characterize the indenter geometry based on the indentation technique. Indenters, with radii smaller than 1 micron, were used to characterize thin films of different nature and thickness. The influence of tip geometry on the critical load results is presented for paint coatings. The reproducibility of the critical load measurement using different indenter tips of identical geometry, as shown in this paper, represents a considerable technological breakthrough in abrasion testing and demonstrates the scratch test's ability to control the manufacturing quality of thin films in an industrial environment.

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