Free-Volume Depth Profile of Polymeric Membranes Studied by Positron Annihilation Spectroscopy:  Layer Structure from Interfacial Polymerization

2007 ◽  
Vol 40 (21) ◽  
pp. 7542-7557 ◽  
Author(s):  
Hongmin Chen ◽  
Wei-Song Hung ◽  
Chia-Hao Lo ◽  
Shu-Hsien Huang ◽  
Mei-Ling Cheng ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Depth Profile ◽  
Interfacial Polymerization ◽  
Layer Structure ◽  
Positron Annihilation Spectroscopy ◽  
Polymeric Membranes

The Depth Profile of Free Volume in Drug Delivery Polymers Studied by Positron Annihilation Spectroscopy

2004 ◽  
Vol 445-446 ◽  
pp. 319-321 ◽  
Author(s):  
Ying Li ◽  
R. Zhang ◽  
H. Chen ◽  
J. Zhang ◽  
Ryoichi Suzuki ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Positron Annihilation ◽  
Free Volume ◽  
Depth Profile ◽  
Positron Annihilation Spectroscopy

scholarly journals Free-volume Characterization of Polysilanes Using Positron Annihilation Spectroscopy.

1999 ◽  
Vol 12 (5) ◽  
pp. 739-742
Author(s):  
Mutsumi Tashiro ◽  
Shu Seki ◽  
Pradeep K. Pujari ◽  
Yoshihide Honda ◽  
Seiichi Tagawa
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Annihilation Spectroscopy

scholarly journals Insightful understanding of the correlations of the microstructure and catalytic performances of Pd@chitosan membrane catalysts studied by positron annihilation spectroscopy

RSC Advances ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 3225-3236 ◽  
Author(s):  
Qi Liu ◽  
Mengdie Xu ◽  
Jing Zhao ◽  
Yudong Wang ◽  
Chenze Qi ◽  
...  
Keyword(s):  
Mass Transport ◽  
Positron Annihilation ◽  
Free Volume ◽  
Positron Annihilation Spectroscopy ◽  
Membrane Catalyst ◽  
Chitosan Membrane ◽  
Transport Channels ◽  
Catalytic Performances

A number of instantaneously connected free volume holes act as mass transport channels of the Pd0@CS membrane catalyst in reactions.

Crosslinked PVA/SSA proton exchange membranes: correlation between physiochemical properties and free volume determined by positron annihilation spectroscopy

2018 ◽  
Vol 20 (44) ◽  
pp. 28287-28299 ◽  
Author(s):  
Mahmoud M. Gomaa ◽  
Christoph Hugenschmidt ◽  
Marcel Dickmann ◽  
Esam E. Abdel-Hady ◽  
Hamdy F. M. Mohamed ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Annihilation Spectroscopy ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Water Molecules ◽  
High Humidity ◽  
Physiochemical Properties ◽  
Low Humidity ◽  
Volume Size

At low humidity (<30 RH%), water molecules begin to fill the intermolecular spaces in the membrane. At high humidity (80 RH%) the membrane swells; the free volume size increases.

On the Limits of Sensitivity of PALS to Incorporated Free Volume Holes in Polymeric Membranes and Sorbents: Effect of sc-CO2 in Polyhexafluoropropylene

2017 ◽  
Vol 373 ◽  
pp. 261-264 ◽  
Author(s):  
Victor Shantarovich ◽  
Valentin Bekeshev ◽  
Nikolai Belov ◽  
Irina Kevdina ◽  
Mikhail Filimonov ◽  
...  
Keyword(s):  
Low Temperature ◽  
Size Distribution ◽  
Positron Annihilation ◽  
Free Volume ◽  
Polymeric Membranes ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Membrane Materials ◽  
Positron Annihilation Lifetime

Positron annihilation lifetime spectroscopy (PALS) is a recognized instrument for the studies of size-distribution of nanopores (intrinsic free volume holes FVH) in polymers, particularly membrane materials. The limits of this application in the case of “alien” pores, produced by swelling of poly (hexafluoro propylene) PHFP in the gas (CO2) in super-critical (sc-) state are discussed. The obtained conclusions are controlled by measurements of low temperature gas (N2) sorption (LTGS) and by comparison of the data with the results on permeation of various gases through the PHFP membrane. Attention is payed to relaxation with time of the newly created FVH in the PHFP membrane.

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