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Release from Silica SBA‐3‐like Mesoporous Fibers: Cross‐Wall Transport and External Diffusion Barrier
Author(s) -
Stempniewicz Magdalena,
Rohwerder Michael,
Marlow Frank
Publication year - 2007
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600408
Subject(s) - diffusion , diffusion barrier , slowdown , molecule , mesoporous material , particle (ecology) , chemical engineering , nanometre , nanotechnology , nanoparticle , mesoporous silica , chemistry , deposition (geology) , materials science , molecular diffusion , chemical physics , layer (electronics) , composite material , organic chemistry , catalysis , law , oceanography , engineering , biology , paleontology , political science , thermodynamics , physics , sediment , geology , operations management , metric (unit) , economics
The transport of guest molecules between adjacent pore channels (cross‐wall transport) is the limiting factor in the release of guest molecules from SBA‐3‐like fibers. This specific mode of diffusion is identified by microscopic observation and studied quantitatively in a UV/Vis‐monitored release experiment. Analysis of release curves reveals that the external particle surface offers resistance to the guest molecules passing through it (external diffusion barrier). This barrier is native to as‐synthesized fibers and can be effectively modified to slow down the release. Extremely effective slowdown is achieved by deposition of a nanometer‐thick layer of sodium silicate, that is, the guest molecules are then safely stored in the particles.