TY - JOUR
T1 - Positron annihilation spectroscopy for the free volume depth profile analysis of multilayer and 2D materials composite membranes
T2 - A review
AU - Widakdo, Januar
AU - Reyes De Guzman, Manuel
AU - Belle Marie Yap Ang, Micah
AU - Hung, Wei Song
AU - Huang, Shu Hsien
AU - Hu, Chien Chieh
AU - Lee, Kueir Rarn
AU - Lai, Juin Yih
N1 - Funding Information:
The authors would like to thank the National Science and Technology Council of Taiwan (NSTC) (NSTC 108-2628-E-011-003-MY3, NSTC 110-2221-E-011-122-MY3, and NSTC 110-2622-E-011-009) for financially supporting this research.
Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/10/1
Y1 - 2023/10/1
N2 - Previous techniques probed only static defects in polymeric membranes. However, spaces within polymer chains must be dynamic, which allows them to move freely. The advent of positron annihilation spectroscopy (PAS) has dispelled the lack of a suitable probe for free volume, which has both a subnanometer dimension (Å–nm) and a very short timescale (10–6–10–13). Since then, PAS has introduced an influx of experimental data on free volume, voids, depth profile, and elemental analysis in 2D and polymeric membranes. But PAS is still in the developing stage. The following requisites propel the development of PAS: (1) more accurate measurement of free volume and voids; (2) characterization of depth profile in composite membranes; (3) analysis of elemental and chemical compositions of membranes; (4) advancement of PAS technology. PAS results are correlated with pervaporation, nanofiltration, microfiltration, ultrafiltration, and gas separation in membrane application. This review article discusses PAS techniques, data analysis, and instrumentation in detail in each requirement. We identify PAS limitations and challenges and comment on past studies that suggested and applied solutions. Furthermore, we introduce the characteristics of PALS technology in polymer composite membranes and describe the application potential of advanced two-dimensional materials.
AB - Previous techniques probed only static defects in polymeric membranes. However, spaces within polymer chains must be dynamic, which allows them to move freely. The advent of positron annihilation spectroscopy (PAS) has dispelled the lack of a suitable probe for free volume, which has both a subnanometer dimension (Å–nm) and a very short timescale (10–6–10–13). Since then, PAS has introduced an influx of experimental data on free volume, voids, depth profile, and elemental analysis in 2D and polymeric membranes. But PAS is still in the developing stage. The following requisites propel the development of PAS: (1) more accurate measurement of free volume and voids; (2) characterization of depth profile in composite membranes; (3) analysis of elemental and chemical compositions of membranes; (4) advancement of PAS technology. PAS results are correlated with pervaporation, nanofiltration, microfiltration, ultrafiltration, and gas separation in membrane application. This review article discusses PAS techniques, data analysis, and instrumentation in detail in each requirement. We identify PAS limitations and challenges and comment on past studies that suggested and applied solutions. Furthermore, we introduce the characteristics of PALS technology in polymer composite membranes and describe the application potential of advanced two-dimensional materials.
KW - 2D membranes
KW - Composite polymeric membranes
KW - Free volume
KW - Nondestructive technique
KW - Positron annihilation spectroscopy
KW - Voids
UR - http://www.scopus.com/inward/record.url?scp=85163150762&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2023.124366
DO - 10.1016/j.seppur.2023.124366
M3 - Review article
AN - SCOPUS:85163150762
SN - 1383-5866
VL - 322
JO - Separation and Purification Technology
JF - Separation and Purification Technology
M1 - 124366
ER -