Characterization of Chemically Modified Pore Surfaces by Small Angle Neutron Scattering

1989 ◽  
Vol 166 ◽  
Author(s):  
C. J. Glinka ◽  
L. C. Sandert ◽  
S. A. Wiset ◽  
N. F. Berk
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Pore Space ◽  
Silica Particles ◽  
Microporous Silica ◽  
Hydrocarbon Chains ◽  
Phase Liquid ◽  
Internal Pore

ABSTRACTSmall angle neutron scattering has been used to characterize the structure of linear hydrocarbon chains chemically grafted to the internal pore surfaces of microporous silica particles. The aim of this work has been to relate the structure of the bonded adsorbate layers in these particles to their performance in, for example, reverse-phase liquid chromatography. By filling the pore space in the modified silica with a solution that matches the scattering density of the silica framework, the scattering from the adsorbate layers is enhanced and provides a sensitive probe of the effective thickness, uniformity and degree of solvent penetration in the layers. Results are presented for both monomeric and polymeric phases of alkyl chains ranging from C8 to C30 bonded to silica particles with a mean pore size of 100 nm.

scholarly journals Morphology of Thin Film Composite Membranes Explored by Small-Angle Neutron Scattering and Positron-Annihilation Lifetime Spectroscopy

Membranes ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 48 ◽  
Author(s):  
Vitaliy Pipich ◽  
Marcel Dickmann ◽  
Henrich Frielinghaus ◽  
Roni Kasher ◽  
Christoph Hugenschmidt ◽  
...  
Keyword(s):  
Thin Film ◽  
Neutron Scattering ◽  
Positron Annihilation ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Film Composite ◽  
Positron Annihilation Lifetime ◽  
Thin Film Composite

The morphology of thin film composite (TFC) membranes used in reverse osmosis (RO) and nanofiltration (NF) water treatment was explored with small-angle neutron scattering (SANS) and positron-annihilation lifetime spectroscopy (PALS). The combination of both methods allowed the characterization of the bulk porous structure from a few Å to µm in radius. PALS shows pores of ~4.5 Å average radius in a surface layer of about 4 μm thickness, which become ~40% smaller at the free surface of the membranes. This observation may correlate with the glass state of the involved polymer. Pores of similar size appear in SANS as closely packed pores of ~6 Å radius distributed with an average distance of ~30 Å. The main effort of SANS was the characterization of the morphology of the porous polysulfone support layer as well as the fibers of the nonwoven fabric layer. Contrast variation using the media H2O/D2O and supercritical CO2 and CD4 identified the polymers of the support layers as well as internal heterogeneities.

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