Document Detail


Characterization of defects and surface structures in microporous materials by HRTEM, HRSEM, and AFM.
MedLine Citation:
PMID:  15306048     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
High-resolution transmission (HRTEM) and high-resolution scanning electron microscopy as well as atomic force microscopy (AFM), X-ray diffraction, and electron diffraction were used for studying the zeolites MFI, MEL, and the MFIMEL intergrowth system. All three zeolites consisted of individual particles having a size in the range of approximately 0.5 m to 5 m. The particle habits varied from rather cubelike to almost spherelike with many intermediate habits. Typically, the particles of these three zeolites were assembled by many individual blocks that differed in the dimension from about 25 nm to 140 nm as well as in the shape from very frequently almost rectangular (for MFI, MEL, and MFIMEL) to sometimes roundish or irregular habits (mainly for MFIMEL). An estimate shows that some 104 up to more than 106 densely packed blocks typically may assemble each individual zeolite particle or, related to the corresponding unit cell dimension, about 108 up to 1010 unit cells. The fine surface structure of zeolite particles was terracelike with steps between adjacent terraces typically in the range of 20 nm to 60 nm; the minimum step measured was approximately 4 nm. A detailed study of the surface topography was performed by AFM, detecting organic molecules at the block intersections. The presence of topological defects was observed by HRTEM and electron diffraction.
Authors:
Gema González; Werner Stracke; Zoraya Lopez; Ulrike Keller; Andrea Ricker; Rudolf Reichelt
Related Documents :
840648 - Physical properties of nucleoprotein cores from adenovirus type 5.
1276388 - Analysis of freeze-fracture electron micrographs by a computer-based technique.
15112558 - Zinc sulfide nanocoating of silica submicron spheres using a single-source method.
16471578 - Investigation of aerosol formation during benzaldehyde photolysis.
8338038 - Variability of fecal energy content measured in healthy women.
22833718 - Putting desire on a budget: dopamine and energy expenditure, reconciling reward and res...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada     Volume:  10     ISSN:  1431-9276     ISO Abbreviation:  Microsc. Microanal.     Publication Date:  2004 Apr 
Date Detail:
Created Date:  2004-08-12     Completed Date:  2004-09-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9712707     Medline TA:  Microsc Microanal     Country:  United States    
Other Details:
Languages:  eng     Pagination:  224-35     Citation Subset:  IM    
Affiliation:
Centro Tecnológico, Laboratorio de Materiales, Instituto Venezolano de Investigaciones Científicas, Apdo. 21827, Caracas 1020 A, Venezuela. gemagonz@ivic.ve
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Heterocyclic Compounds / chemistry*
Microscopy, Atomic Force / methods
Microscopy, Electron / methods
Microscopy, Electron, Scanning / methods
Models, Molecular
Molecular Conformation
Reproducibility of Results
Chemical
Reg. No./Substance:
0/Heterocyclic Compounds

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  A morphological and cytochemical study of the interaction between Paracoccidiodes brasiliensis and n...
Next Document:  Measurement of lattice displacements at planar defects in 2H and 18R martensites.