Atomistic Simulation of Orientation of Methyl Groups and Methylene Bisectors, and Surface Segregation, in Freely Standing Thin Films of Atactic Poly(ethylene-co-propylene)

2004 ◽  
Vol 108 (39) ◽  
pp. 14830-14839 ◽  
Author(s):  
Sagar S. Rane ◽  
Wayne L. Mattice ◽  
Ali Dhinojwala
2020 ◽  
Vol 12 (3) ◽  
pp. 03007-1-03007-8
Author(s):  
N. P. Klochko ◽  
◽  
K. S. Klepikova ◽  
D. O. Zhadan ◽  
V. R. Kopach ◽  
...  

2012 ◽  
Vol 23 (49) ◽  
pp. 495701 ◽  
Author(s):  
Venkata Sai Kiran Chakravadhanula ◽  
Christian Kübel ◽  
Tomislav Hrkac ◽  
Vladimir Zaporojtchenko ◽  
Thomas Strunskus ◽  
...  

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 225
Author(s):  
Pei-Ju Chen ◽  
Hsien-Yeh Chen ◽  
Wei-Bor Tsai

A facial, versatile, and universal method that breaks the substrate limits is desirable for antifouling treatment. Thin films of functional poly-p-xylylenes (PPX) that are deposited using chemical vapor deposition (CVD) provide a powerful platform for surface immobilization of molecules. In this study, we prepared an alkyne-functionalized PPX coating on which poly (sulfobetaine methacrylate-co-Az) could be conjugated via click chemistry. We found that the conjugated polymers were very stable and inhibited cell adhesion and protein adsorption effectively. The same conjugation strategy could also be applied to conjugate azide-containing poly (ethylene glycol) and poly (NIPAAm). The results indicate that our method provides a simple and robust tool for fabricating antifouling surfaces on a wide range of substrates using CVD technology of functionalized poly (p-xylylenes) for biosensor, diagnostics, immunoassay, and other biomaterial applications.


2019 ◽  
Author(s):  
Paul Markus ◽  
Daniel E Martínez-Tong ◽  
Georg Papastavrou ◽  
Angel Alegria

<div><div><div><p>The effect of humidity on the ionic transport in the amorphous phase of poly(ethylene oxide) thin films has been studied by via local dielectric spectroscopy. We explored a controlled humidity range between 15 %RH and 50 %RH. AFM-based local dielectric imaging allowed to obtain simultaneously the thin films topography and the corresponding dielectric contrast maps. No humidity effect on the film topography was observed whereas large variation of the dielectric signal could be detected. In addition, we observed a clear dielectric contrast in different locations on the thin film surface. At selected regions with high contrast in the dielectric maps, we performed nanoDielectric Spectroscopy (nDS) measurements covering the frequency range from 10 Hz to 100 kHz. By modeling these spectroscopy results, we quantified the conductivity of the amorphous phase of the semicrystalline poly(ethylene oxide) films. The crystalline fraction of the PEO thin films was extracted and found to be about 36%, independently of humidity. However, the average conductivity increased drastically from 2×10-10 to 5×10-9 S/cm, by changing environmental humidity in the explore %RH range.</p></div></div></div>


1998 ◽  
Vol 530 ◽  
Author(s):  
A.M. Mayes ◽  
D.J. Irvine ◽  
L.G. Griffith

AbstractAn ideal surface for many biomaterials applications would resist nonspecific protein adsorption while at the same time providing a means for specifically signaling cells to guide survival, growth, migration, and differentiation. This work was directed towards the investigation of model systems and clinically-applicable materials which provide both of these surface requirements. Model systems were prepared by chemically grafting end-functionalized star poly(ethylene oxide) (PEO) to surfaces. The end-grafted polymers provide a means for cell-signaling through coupling of peptides to the free chain ends. Protein adsorption on star vs. linear grafted layers was compared. To further understand these results, neutron reflectivity studies were carried out in situ for solvated PEO surfaces to determine the concentration profiles of the swollen grafted layers. Surprisingly, grafted PEO layers which resist protein adsorption have low concentrations of polymer segments throughout the swollen layer. We find that dense star architectures which might be expected to impart improved protein resistance in fact allow small proteins to adsorb. For clinical materials, a novel approach to the surface modification of poly(lactide) (PLA) has been taken by surface segregating a comb copolymer containing a PLA backbone and poly(ethylene glycol) teeth. The ends of the teeth provide sites for surface tethering of peptide ligands. Comb surfaces without tethered ligands are cell adhesion resistant, indicating strong protein adsorption resistance. By then incorporating an adhesion ligand, modulation of cell morphology on comb surfaces has been demonstrated. Finally, the surface segregation of the comb to the surface of PLA was shown via cell attachment assays and XPS measurements.


2011 ◽  
Vol 44 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Aleš Doliška ◽  
Alenka Vesel ◽  
Metod Kolar ◽  
Karin Stana-Kleinschek ◽  
Miran Mozetič

2018 ◽  
Vol 51 (5) ◽  
pp. 1626-1635 ◽  
Author(s):  
Binghua Wang ◽  
Shaohua Tang ◽  
Yan Wang ◽  
Changyu Shen ◽  
Renate Reiter ◽  
...  

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