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Scanning electron microscopy of wet synthetic polymers
Šlouf, Miroslav; Studenovská, Hana; Rypáček, František; Sikora, Antonín
2007 - English
Synthetic polymers with high content of water (wet synthetic polymers,hydrogels) are frequently used in tissue engineering. Investigation of their 3D-structure by means of scanning electron microscopy is very difficult: in a standard electron microscope water almost immediately evaporates and the structure breaks down. Nevertheless, hydrogels morphology can be visualised by means of low-vacuum scanning electron microscopy in cryo conditions (cryoLVSEM) and by environmental scanning electron microscopy (ESEM). The two techniques are described and compared. Syntetické polymery s vysokým obsahem vody (mokré syntetické polymery, hydrogely) se často používají jako umělé tkáně. Studium jejich 3D struktury pomocí elektronové mikroskopie je velmi obtížné: ve standardním elektronovém mikroskopu se totiž voda ze vzorku téměř okamžitě odpaří a jeho struktura se zhroutí. Nicméně je možno strukturu hydrogelů pozorovat pomocí specielních technik, jako je mrazová nízkovakuová rastrovací elektronová mikroskopie (cryoLVSEM) a environmenální rastrovací elektronová mikroskopie (ESEM). Tyto dvě techniky jsou v příspěvku popsány a porovnány.
Keywords:
ESEM; environmental scanning electron microscopy; low-vacuum microscopy
Available at various institutes of the ASCR
Scanning electron microscopy of wet synthetic polymers
Synthetic polymers with high content of water (wet synthetic polymers,hydrogels) are frequently used in tissue engineering. Investigation of their 3D-structure by means of scanning electron microscopy ...
Poly(methyl methacrylate) inorganic filler composites: understanding the role of matrix structure in presence of adhering filler
Dušková, Miroslava; Dušek, Karel; Zelenka, J.
2007 - English
The study showed that the properties of a glassy composite with crosslinked matrix adhering to the rigid filler particles are sensitive to the polymer network structure of the matrix . It was proved by morphological, swelling and mechanical studies that the adhesion between the crosslinked poly(methyl methacrylate) matrix and the ATH filler is maintained in the swollen state and during small-strain. In the swollen state or at temperatures about 60 °C above Tg, the mechanical relaxations are relatively fast and equilibrium can be reached within approximately one hour. A model of equilibrium swelling constrained by surfaces of various geometries has been developed based on statistical thermodynamics of (Gaussian) networks. Bylo prokázáno, že vlastnosti kompozitu sesíťovaného poly(metyl methakrylátu) a tuhého plniva typu Al.sub.2./sub.O.sub.3./sub.3H.sub.2./sub.O závisely na struktuře matrice. Hodnoty rovnovážných smykových modulů (měřených nad teplotou Tg kompozitu) a rovnovážného nabotnání ukazují vliv geometrických omezení způsobených přítomností plniva. Byl vyvinut model rovnovážného nabotnání v omezeném objemu, které je důsledkem spojení objektů s různou objemovou roztažností. Model zohledňuje geometrická omezení dána přítomností plniva, jehož objem se při botnání kompozitu nemění, a které může mít různou geometrii. Model změn v matrici je založen na statistické termodynamice Gaussovských sítí.
Keywords:
polymer composite; crosslinked polymer matrix; particulate filler
Available at various institutes of the ASCR
Poly(methyl methacrylate) inorganic filler composites: understanding the role of matrix structure in presence of adhering filler
The study showed that the properties of a glassy composite with crosslinked matrix adhering to the rigid filler particles are sensitive to the polymer network structure of the matrix . It was proved ...
Physical properties of PE nanocomposites as a function of percentage of wood fibres
Kokta, B. V.; Kwei-Nam, L.; Fortelný, Ivan; Lednický, František; Kruliš, Zdeněk
2007 - English
We investigated the formation of an optimal compatibilizing system for the hybride composite polyethylene -birch wood fibers-nanoclay by combining basic principles for compatibilization, i.e. addition of maleated polyethylene and peroxide. Studovali jsme tvorbu optimálního kompatibilizačního systému pro hybridní kompozit polyethylenu s vlákny březového dřeva a nanočástic jílu za pomoci kombinace základních principů kompatibilizace, tj. přidání maleovaného polyethylenu a peroxidu.
Keywords:
PE nanocomposites; wood fibres
Available at various institutes of the ASCR
Physical properties of PE nanocomposites as a function of percentage of wood fibres
We investigated the formation of an optimal compatibilizing system for the hybride composite polyethylene -birch wood fibers-nanoclay by combining basic principles for compatibilization, i.e. addition ...
SERS spectral probing of dimers of silver nanoparticles molecularly bridged by various molecules
Šmejkal, P.; Vlčková, B.; Moskovits, M.; Pavel, I.; Sládková, M.; Pavlova, Ewa; Šlouf, Miroslav
2006 - English
The ability of several molecules to act as linkers for Ag nanoparticles was tested. As new prospective linker molecules, dimercaptocarborane, ethidium bromide and 5,10,15,20-tetrakis(4-sulphonatophenyl)porphine (TSPP) were selected owing to their terminal functional groups, which can assemble the Ag nanoparticles together to form a dimer. Byla zkoumána schopnost několika molekul účinkovat jako spojka Ag nanočástic. Jako nové perspektivní spojovací molekuly byly vybrány dimerkaptokarboran, ethidium bromid a TSPP na základě svých koncových funkčních skupin, které dokáží spojit Ag nanočástice do dimerů.
Keywords:
moleculary bridged Ag nanoparticle dimers; Ag nanoparticles dimer preparation; small Ag nanoparticle aggregates
Available at various institutes of the ASCR
SERS spectral probing of dimers of silver nanoparticles molecularly bridged by various molecules
The ability of several molecules to act as linkers for Ag nanoparticles was tested. As new prospective linker molecules, dimercaptocarborane, ethidium bromide and ...
New metal arylphosphonates
Zima, Vítězslav; Svoboda, Jan; Beneš, L.; Melánová, Klára
2006 - English
New metal arylphosphonates were synthesized and characterized. Byly připraveny a charakterizovány nové arylfosfonáty kovů.
Keywords:
cooper
Available at various institutes of the ASCR
New metal arylphosphonates
New metal arylphosphonates were synthesized and characterized.
Byly připraveny a charakterizovány nové arylfosfonáty kovů.
The influence of acidity on polymerization of aniline: Interpretation of large number of spectra using factor analysis
Šeděnková, Ivana; Trchová, Miroslava; Stejskal, Jaroslav; Bok, J.
2006 - English
The influence of acidity on the final morphology of aniline polymerization products was studied. S využití in situ FTIR spektroskopie byl studován vliv kyselosti na výslednou morfologii produktů polymerizace anilínu.
Keywords:
aniline polymerization; factor analysis; nanotubes
Available at various institutes of the ASCR
The influence of acidity on polymerization of aniline: Interpretation of large number of spectra using factor analysis
The influence of acidity on the final morphology of aniline polymerization products was studied....
Materials for optical and electrical phase change memories - structure properties and application
Frumar, M.; Přikryl, J.; Vlček, Milan; Beneš, L.; Frumarová, Božena; Hrdlička, M.; Wágner, T.
2006 - English
A review of materials and principles used in optical and electrical data storage based on phase changes is given, the composition structure, properties and the ways of preparation of thin films of the materials already used, or potentially applicable, are discussed. The problems of fast crystallization and amorphization as well as problems of stability of amorphous state and of the storage at elevated temperatures are mentioned. Je uveden přehled materiálů a principů pro optické a elektrické uchovávání dat založených na fázové změně. Je diskutováno složení, struktura, vlastnosti a způsoby přípravy tenkých vrstev užívaných materiálů. Problémy rychlé krystalizace a amortizace a též problémy stability amorfních stavů a uchování při zvýšené teplotě je uvedeno.
Keywords:
phase changes
Available at various institutes of the ASCR
Materials for optical and electrical phase change memories - structure properties and application
A review of materials and principles used in optical and electrical data storage based on phase changes is given, the composition structure, properties and the ways of preparation of thin films of the ...
Influence of the clay modification on the degree of dispersion and final properties of epoxy-clay nanocomposites
Rýznarová, B.; Zelenka, J.; Lednický, František; Baldrian, Josef
2006 - English
The effect of four different clay surface modifiers on the degree of dispersion and final properties of epoxy-clay nanocomposites was studied. Byl studován vliv čtyř různých modifikátorů povrchu jílu na stupeň dispergace a konečné vlastnosti nanokompozitů epoxid-montmorilonit.
Keywords:
epoxy-clay nanocomposites; organoclay; clay surface modification
Available at various institutes of the ASCR
Influence of the clay modification on the degree of dispersion and final properties of epoxy-clay nanocomposites
The effect of four different clay surface modifiers on the degree of dispersion and final properties of epoxy-clay nanocomposites was studied....
Influence of the phase separation of active components on the solar cell performance
Podhájecká, Klára; Pfleger, Jiří
2006 - English
The influence of solvent vapor treatment on organic photovoltaic cells based on .pi.-conjugated polymer poly[1-(4-trimethylsilylphenyl)-2-phenylvinylene], and a low molecular-weight compound: N,N´-di(pent-3-yl)-perylene-3,4:9,10-bis(dicarboximide) was investigated. Byl zkoumán vliv působení par organického rozpouštědla na fotovoltaické články tvořené .pi.-konjugovaným polymerem, poly[1-(4-trimethylsilylfenyl)-2-fenylvinylen]em, obsahujícím nízkomolekulární organickou příměs N,N'-di(pent-3-yl)-perylen-3,4:9,10-bis(dicarboximid)u.
Keywords:
organic photovoltaic devices; heterojunction; postprocessing vapor treatment
Available at various institutes of the ASCR
Influence of the phase separation of active components on the solar cell performance
The influence of solvent vapor treatment on organic photovoltaic cells based on .pi.-conjugated polymer poly[1-(4-trimethylsilylphenyl)-2-phenylvinylene], and a low molecular-weight compound: ...
Surface and mechanical properties of organic - inorganic nanocomposite coating films
Špírková, Milena; Bláhová, O.; Farkačová, T.; Benešová, J.
2006 - English
Surface hardness of transparent colorless epoxy-based organic-inorganic nanocomposite coatings was investigated by atomic force microscopy, nanoindentation and the Persoz pendulum test. The influence of mechanical properties on the measured surface characteristics is discussed. Pomocí mikroskopie atomových sil, nanoindentace a kyvadlového testu typu Persoz byla studována povrchová tvrdost bezbarvých transparentních organicko - anorganických nanokompozitních nátěrů. Rovněž je diskutován vliv mechanických vlastností na měřené povrchové charakteristiky.
Keywords:
nanocomposite; coating; atomic force microscopy
Available at various institutes of the ASCR
Surface and mechanical properties of organic - inorganic nanocomposite coating films
Surface hardness of transparent colorless epoxy-based organic-inorganic nanocomposite coatings was investigated by atomic force microscopy, nanoindentation and the Persoz pendulum test. The influence ...
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