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.

scholarly journals Positron Annihilation Spectroscopy and Small Angle Neutron Scattering Characterization of Nanostructural Features in Irradiated Fe-Cu-Mn Alloys

2000 ◽  
Vol 650 ◽  
Author(s):  
B. D. Wirth ◽  
P. Asoka-Kumar ◽  
R. H. Howell ◽  
G. R. Odette ◽  
P. A. Sterne
Keyword(s):  
Neutron Scattering ◽  
Positron Annihilation ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nuclear Reactor ◽  
Positron Annihilation Spectroscopy ◽  
Peak Hardness ◽  
The Matrix ◽  
Complementary Techniques

ABSTRACTRadiation embrittlement of nuclear reactor pressure vessel steels results from a high number density of nanometer sized Cu-Mn-Ni rich precipitates (CRPs) and sub-nanometer matrix features, thought to be vacancy-solute cluster complexes (VSC). However, questions exist regarding both the composition of the precipitates and the defect character and composition of the matrix features. We present results of positron annihilation spectroscopy (PAS) and small angle neutron scattering (SANS) characterization of irradiated and thermally aged Fe-Cu and Fe-Cu-Mn alloys. These complementary techniques provide insight into the composition and character of both types of nanoscale features. The SANS measurements indicate populations of CRPs and VSCs in both alloys. The CRPs are coarser in the Fe-Cu alloy and the number densities of CRP and VSC increase with the addition of Mn. The PAS involved measuring both the positron lifetimes and the Doppler broadened annihilation spectra in the high momentum region to provide elemental sensitivity at the annihilation site. The spectra in Fe-Cu-Mn specimens thermally aged to peak hardness at 450°C and irradiated at 288°C are nearly identical to elemental Cu. Positron lifetime and spectrum measurements in Fe-Cu specimens irradiated at 288°C clearly show the existence of long lifetime (∼500 ps) open volume defects, which also contain Cu. Thus the SANS and PAS provide a self-consistent picture of nanostructures composed of CRPs and VSCs and tend to discount high Fe concentrations in the CRPs.

Structural characterization of spray-dried microgranules by spin-echo small-angle neutron scattering

2021 ◽  
Vol 378 ◽  
pp. 680-684
Author(s):  
Priyanka Biswas ◽  
Debasis Sen ◽  
Wim Bouwman
Keyword(s):  
Neutron Scattering ◽  
Structural Characterization ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Spin Echo ◽  
Spray Dried

Characterization of polydimethylsiloxane pervaporation membranes using small-angle neutron scattering

2011 ◽  
Vol 378 (1-2) ◽  
pp. 194-202 ◽  
Author(s):  
Ghanshyam L. Jadav ◽  
Vinod K. Aswal ◽  
Puyam S. Singh
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering
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