scholarly journals Investigation of the morphology and surface properties of crosslinked poly(urethane-ester-siloxane)s

2012 ◽  
Vol 66 (6) ◽  
pp. 813-821 ◽  
Author(s):  
Jasna Dzunuzovic ◽  
Marija Pergal ◽  
Vesna Vodnik ◽  
Milena Spírková ◽  
Rafał Poręba ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Water Absorption ◽  
Surface Properties ◽  
Microphase Separation ◽  
Crosslinking Agent ◽  
Hydrophobic Surface ◽  
Sem Analysis ◽  
Force Microscopy ◽  
Hyperbranched Polyesters ◽  
Atomic Force

Two series of crosslinked poly(urethane-ester-siloxane)s were synthesized from ?,?-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO), 4,4?-methylenediphenyl diisocyanate and Boltorn? hyperbranched polyesters of the second and third pseudo generation, by a two-step polymerization in solution. The effect of the EO-PDMS-EO content and functionality of the applied crosslinking agent on the morphology and surface properties of the prepared poly(urethane-ester-siloxane)s was investigated by FTIR spectroscopy, small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and water absorption measurement. Different techniques (FTIR peak deconvolution, SAXS and AFM) revealed that decrease of the crosslinking agent functionality and EO-PDMS-EO content promotes microphase separation in the synthesized poly(urethane-ester-siloxane)s. SEM analysis and water absorption experiments showed that due to the hydrophobic character of EO-PDMS-EO and its ability to migrate to the surface of poly(urethane-ester-siloxane)s, samples synthesized with higher EO-PDMS-EO content and crosslinking agent of lower functionality have more hydrophobic surface and better waterproof performances. The obtained results indicate that the synthesis of poly(urethane-ester-siloxane)s based on EO-PDMS-EO and Boltorn? hyperbranched polyesters leads to the creation of networks with interesting morphological and surface properties, which can be easily tailored by changing the content of EO-PDMS-EO segment or functionality of hyperbranched polyester.

scholarly journals Study on the morphology and thermomechanical properties of poly(urethane-siloxane) networks based on hyperbranched polyester

2013 ◽  
Vol 67 (6) ◽  
pp. 871-879
Author(s):  
Marija Pergal ◽  
Jasna Dzunuzovic ◽  
Milena Spírková ◽  
Rafal Poręba ◽  
Milos Steinhart ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Microphase Separation ◽  
Soft Segment ◽  
Hydrophobic Surface ◽  
Crosslinking Density ◽  
Thermomechanical Properties ◽  
Hyperbranched Polyester ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force

Two series of polyurethane films based on hyperbranched polyester of the second pseudogeneration (Boltorn?), 4,4'-methylenediphenyl diisocyanate and two different siloxane prepolymers, ?,?-dihydroxy-(ethylene oxide-poly(dimethylsiloxane)-ethylene oxide) (EO-PDMS-EO) and ?,?-dihydroxypropyl-poly(dimethylsiloxane) (HP-PDMS), were prepared by two-step polymerization in solution. The influence of the type and content of soft segment on the morphology, thermomechanical and surface properties of the synthesized polyurethanes was studied by atomic force microscopy (AFM), small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), dynamic mechanical thermal analysis (DMTA) and water absorption measurements. It was found that these techniques confirmed existence of microphase separated morphology. Synthesized polyurethanes exhibited two glass transition temperatures and one second relaxation process. The results showed that polyurethanes based on HP-PDMS had higher surface roughness, better microphase separation and waterproof performances. Samples synthesized with lower PDMS content had less hydrophobic surface, but higher crosslinking density and better thermomechanical properties. (Projekat Ministarstva nauke Republike Srbije, br. 172062]

AFM study of the dynamics of α-alumina surface faceting during high-temperature processing

1995 ◽  
Vol 53 ◽  
pp. 334-335 ◽  
Author(s):  
Michael W. Bench ◽  
Jason R. Heffelfinger ◽  
C. Barry Carter
Keyword(s):  
High Temperature ◽  
Thin Foil ◽  
Sem Analysis ◽  
Conductive Coatings ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Formation And Evolution ◽  
High Temperature Processing ◽  
Nominal Surface

To gain a better understanding of the surface faceting that occurs in α-alumina during high temperature processing, atomic force microscopy (AFM) studies have been performed to follow the formation and evolution of the facets. AFM was chosen because it allows for analysis of topographical details down to the atomic level with minimal sample preparation. This is in contrast to SEM analysis, which typically requires the application of conductive coatings that can alter the surface between subsequent heat treatments. Similar experiments have been performed in the TEM; however, due to thin foil and hole edge effects the results may not be representative of the behavior of bulk surfaces.The AFM studies were performed on a Digital Instruments Nanoscope III using microfabricated Si3N4 cantilevers. All images were recorded in air with a nominal applied force of 10-15 nN. The alumina samples were prepared from pre-polished single crystals with (0001), , and nominal surface orientations.

scholarly journals Antibacterial Properties of Plasma-Activated Perfluorinated Substrates with Silver Nanoclusters Deposition

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 182
Author(s):  
Petr Slepička ◽  
Silvie Rimpelová ◽  
Nikola Slepičková Kasálková ◽  
Dominik Fajstavr ◽  
Petr Sajdl ◽  
...  
Keyword(s):  
Surface Properties ◽  
Antibacterial Properties ◽  
Argon Plasma ◽  
Antimicrobial Effect ◽  
Silver Nanoclusters ◽  
Plasma Modification ◽  
Material Surface ◽  
Silver Deposition ◽  
Force Microscopy ◽  
Atomic Force

This article is focused on the evaluation of surface properties of polytetrafluoroethylene (PTFE) nanotextile and a tetrafluoroethylene-perfluoro(alkoxy vinyl ether) (PFA) film and their surface activation with argon plasma treatment followed with silver nanoclusters deposition. Samples were subjected to plasma modification for a different time exposure, silver deposition for different time periods, or their combination. As an alternative approach, the foils were coated with poly-L-lactic acid (PLLA) and silver. The following methods were used to study the surface properties of the polymers: goniometry, atomic force microscopy, and X-ray photoelectron microscopy. By combining the aforementioned methods for material surface modification, substrates with antibacterial properties eliminating the growth of Gram-positive and Gram-negative bacteria were prepared. Studies of antimicrobial activity showed that PTFE plasma-modified samples coated with PLLA and deposited with a thin layer of Ag had a strong antimicrobial effect, which was also observed for the PFA material against the bacterial strain of S. aureus. Significant antibacterial effect against S. aureus, Proteus sp. and E. coli has been demonstrated on PTFE nanotextile plasma-treated for 240 s, coated with PLLA, and subsequently sputtered with thin Ag layer.

scholarly journals Synthesis of amphiphilic ABA triblock oligomer via ATRP and its surface properties

2017 ◽  
Vol 95 (5) ◽  
pp. 605-611 ◽  
Author(s):  
Lei Wang ◽  
Shaoqing Wen ◽  
Zhanxiong Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Microphase Separation ◽  
Gel Permeation Chromatography ◽  
Contact Angles ◽  
Chemical Compositions ◽  
Water Contact ◽  
Force Microscopy ◽  
Atomic Force ◽  
Poly Ethylene ◽  
Magnetic Resonances

A series of novel amphiphilic ABA-type poly(tridecafluorooctylacrylate)-poly(ethylene glycol)-poly(tridecafluorooctylacrylate) (henceforth referred to as p-TDFA-PEG-p-TDFA) triblock oligomers were successfully synthesized via atom transfer radical polymerization (ATRP) using well-defined Br-PEG-Br as macroinitiator and copper as catalyst. The block oligomers were characterized by Fourier transform infrared (FTIR) spectroscopy and 1H and 19F nuclear magnetic resonances (NMR). Gel permeation chromatography (GPC) showed that the block oligomers have been obtained with narrow molecular weight distributions of 1.22–1.33. X-ray photoelectron spectroscopy (XPS) was carried out to confirm the attachment of p-TDFA-PEG-p-TDFA onto the silicon substrate, together with the chemical compositions of p-TDFA-PEG-p-TDFA. The wetabilities of the oligomer films were measured by water contact angles (CAs). Water CAs of p-TDFA-PEG-p-TDFA film were measured and their morphologies were tested by atomic force microscopy (AFM). The result showed that the CAs of the oligomer films, which possess fluoroalkyl groups assembled on the outer surface, increase after heating due to the migration of fluoroalkyl groups and the resulted microphase separation of the p-TDFA-PEG-p-TDFA.

scholarly journals An investigation of surface properties, local elastic modulus and interaction with simulated pulmonary surfactant of surface modified inhalable voriconazole dry powders using atomic force microscopy

RSC Advances ◽  
2016 ◽  
Vol 6 (31) ◽  
pp. 25789-25798 ◽  
Author(s):  
Sumit Arora ◽  
Michael Kappl ◽  
Mehra Haghi ◽  
Paul M. Young ◽  
Daniela Traini ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Modulus ◽  
Surface Properties ◽  
Pulmonary Surfactant ◽  
Dry Powders ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Modified ◽  
Spray Dried

l-Leucine modified voriconazole spray dried micropartcles.

scholarly journals Microphase separation at the surface of block copolymers, as studied with atomic force microscopy

2000 ◽  
Vol 19 (4) ◽  
pp. 381-395 ◽  
Author(s):  
A Rasmont ◽  
Ph Leclère ◽  
C Doneux ◽  
G Lambin ◽  
J.D Tong ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Block Copolymers ◽  
Microphase Separation ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Surface Properties of Alginate/Chitosan Biofilm for Wound Healing Application

2020 ◽  
Vol 1010 ◽  
pp. 602-607
Author(s):  
Maizlinda Izwana Idris ◽  
Mohammed Firdaus Adzhari ◽  
Siti Natrah Abdul Bakil ◽  
Tee Chuan Lee ◽  
Mohamad Ali Selimin ◽  
...  
Keyword(s):  
Contact Angle ◽  
Wound Healing ◽  
Surface Properties ◽  
Healing Process ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Force Microscopy ◽  
Good Surface ◽  
Atomic Force ◽  
Biopolymer Film

This work focuses on the fabrication of film based on natural biopolymers for wound healing application. Alginate and chitosan were choosen because of their oustanding properties such as biocompatible, hydrophilic and non-toxic. Earlier, the biopolymer film was fabricated by using alginate 1% wt and chitosan 1% wt. solutions at volume ratios of 99:1 and 97:3. Next, the biopolymer film solution was cross-linked with 1M CaCl2.2H2O for two hours and later dried for 24 hours at room temperature. Then, the surface properties of the prepared biopolymer films were characterised via Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM) and contact angle measurement. It was observed that the surface of the biopolymer film became rougher as the volume of the chitosan increases. This condition was confirmed with average surface roughness, RA for biopolymer film with ratio of 97:3 resulted in higher values. Also it was found that the surface of biopolymer films were hydrophilic after the contact angle was less than 90°. This can be concluded that the biopolymer based on alginate/chitosan is a promising candidate for wound healing materials particularly with good surface properties for faster healing process at the wound areas.

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