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Titolo:
EELS analysis of PMMA at high spatial resolution
Autore:
Varlot, K; Martin, JM; Quet, C;
Indirizzi:
Inst Natl Sci Appl Lyon, Grp Etud Met Phys & Phys Mat, CNRS, UMR 5510, F-69621 Villeurbanne, France Inst Natl Sci Appl Lyon Villeurbanne France F-69621 Villeurbanne, France Ecole Cent Lyon, Lab Tribol & Dynam Syst, UMR 5513, F-69131 Ecully, FranceEcole Cent Lyon Ecully France F-69131 , UMR 5513, F-69131 Ecully, France ELF Atochem, Grp Rech Lacq, F-64170 Artix, France ELF Atochem Artix France F-64170 m, Grp Rech Lacq, F-64170 Artix, France
Titolo Testata:
MICRON
fascicolo: 4, volume: 32, anno: 2001,
pagine: 371 - 378
SICI:
0968-4328(200106)32:4<371:EAOPAH>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
ENERGY LOSS SPECTROSCOPY; ORGANIC POLYMERS; ELECTRON; MICROSCOPY; DAMAGE;
Keywords:
transmission electron microscope; electron energy-loss spectroscopy; polymers; poly(methyl methacrylate); molecular orbital; EHT; irradiation damage; multiple-hit theory; FEG;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
16
Recensione:
Indirizzi per estratti:
Indirizzo: Varlot, K Inst Natl Sci Appl Lyon, Grp Etud Met Phys & Phys Mat, CNRS, UMR5510, 20 Ave A Einstein, F-69621 Villeurbanne, France Inst Natl Sci Appl Lyon 20 Ave A Einstein Villeurbanne France F-69621
Citazione:
K. Varlot et al., "EELS analysis of PMMA at high spatial resolution", MICRON, 32(4), 2001, pp. 371-378

Abstract

We performed the electron energy-loss spectroscopic (EELS) analysis of electron-sensitive polymers in the analytical transmission electron microscopein order to evaluate the possibility to obtain chemical information on polymers at a nanometre scale (i.e, at 2.4 nm diameter probe). In the acquiredspectra, we propose an identification of the ELNES fine structure to the different chemical bonding in agreement with molecular orbital calculations (EHT) and with previous XANES experiments. The main results confirm that poly(methyl mettacrylate) (PMMA) is very sensitive to electrons when a large probe size is used, with a critical dose of about 10(2) C m(-2). However a high dose rate in a nanometre diameter electron beam is less destructive and the EELS spectra of far less degraded PMMA could be obtained even at 10(7) C m(-2). Irradiation damage was however thought to be the main limitation of the field-emission gun microscope, since high electron doses are required to acquire an EELS spectrum. This surprising behaviour was already observed in the case of poly(ethylene terephthalate), which is however more resistant to the electron beam (Varlot et al.,1997. Ultramicroscopy 68 (2, 123-133). Several possible explanations were studied, such as the influence of the accelerating voltage, a wrong calculation of the electron dose, the excitation delocalisation and the electron dose rate. (C) 2001 Elsevier Science Ltd. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 17:10:03