Molecular pore size characterization within chitosan biopolymer using positron annihilation lifetime spectroscopy

2010 ◽  
Vol 64 (23) ◽  
pp. 2635-2637 ◽  
Author(s):  
D. Chaudhary ◽  
M.R. Went ◽  
K. Nakagawa ◽  
S.J. Buckman ◽  
J.P Sullivan
Keyword(s):  
Pore Size ◽  
Positron Annihilation ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Annihilation Lifetime ◽  
Size Characterization ◽  
Chitosan Biopolymer

Pore Size Determination of TEMPO-Oxidized Cellulose Nanofibril Films by Positron Annihilation Lifetime Spectroscopy

2011 ◽  
Vol 12 (11) ◽  
pp. 4057-4062 ◽  
Author(s):  
Hayaka Fukuzumi ◽  
Tsuguyuki Saito ◽  
Shinichiro Iwamoto ◽  
Yoshiaki Kumamoto ◽  
Toshiyuki Ohdaira ◽  
...  
Keyword(s):  
Pore Size ◽  
Positron Annihilation ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Oxidized Cellulose ◽  
Size Determination ◽  
Cellulose Nanofibril ◽  
Positron Annihilation Lifetime

scholarly journals Open Porosity and Pore Size Distribution of Mesoporous Silica Films Investigated by Positron Annihilation Lifetime Spectroscopy and Ellipsometric Porosimetry

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3371
Author(s):  
Bangyun Xiong ◽  
Jingjing Li ◽  
Chunqing He ◽  
Jiale Lai ◽  
Xiangjia Liu ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Positron Annihilation ◽  
Open Porosity ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Silica Films ◽  
Ellipsometric Porosimetry ◽  
Positron Annihilation Lifetime

Tunable mesoporous silica films were prepared though a sol-gel process directed by the self-assembly of various triblock copolymers. Positron annihilation γ-ray energy spectroscopy and positron annihilation lifetime spectroscopy (PALS) based on intense pulsed slow positron beams as well as ellipsometric porosimetry (EP) combined with heptane adsorption were utilized to characterize the open porosity/interconnectivity and pore size distribution for the prepared films. The consistency between the open porosities was examined by the variations of orthopositronium (o-Ps) 3γ annihilation fractions and the total adsorbed volumes of heptane. The average pore sizes deduced by PALS from the longest-lived o-Ps lifetimes are in good agreement with those by EP on the basis of the Barrett–Joyner–Halenda model, as indicated by a well fitted line of slope k = 1. The results indicate that the EP combined with heptane adsorption is a useful method with high sensitivity for calibrating the mesopore size in highly interconnected mesoporous films, whereas PALS is a novel, complementary tool for characterizing both closed and open pores in them.

Positron Annihilation Lifetime Spectroscopy (Pals) Application in Metal Barrier Layer Integrity for Porous Low-K Materials

2001 ◽  
Vol 686 ◽  
Author(s):  
Simon Lin ◽  
Jia-Ning Sun ◽  
David W. Gidley ◽  
Jeffrey T. Wetzel ◽  
K.A. Monnig ◽  
...  
Keyword(s):  
Pore Size ◽  
Positron Annihilation ◽  
Barrier Layer ◽  
Large Scale ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Small Scale ◽  
Barrier Integrity ◽  
Positron Annihilation Lifetime ◽  
Low K ◽  
Metal Barrier

AbstractPositron Annihilation Lifetime Spectroscopy (PALS) (1, 2) is a useful tool to pre-screen metal barrier integrity for Si-based porous low-k dielectrics. Pore size of low-k, thickness of metal barrier Ta, positronium (Ps) leakage from PALS, trench sidewall morphology, electrical test from one level metal (1LM) pattern wafer and Cu diffusion analysis were all correlated. Macro-porous low-k (pore size >= 200A) and large scale meso-porous low-k (>50∼200A) encounter both Ps leakage and Cu diffusion into low-k dielectric in the 0.25μmL/0.3μmS structures when using SEMATECH in-house PVD Ta 250A as barrier layer. For small scale meso-porous (>20∼50A) and micro-porous (<=20A) low-k, no Ps leakage and no Cu diffusion into low-k were observed even with PVD Ta 50A, which is proved also owing to sidewall densification to seal all sidewall pores due to plasma etch and ash. For future technology, smaller pore size of porous Si-based low-k (=< 50A) will be preferential for dense low-k like trench sidewall to avoid metal barrier integrity due to coverage problems from sidewall pores.

Hexadecane in SiO2 Aerogels

2012 ◽  
Vol 733 ◽  
pp. 107-110 ◽  
Author(s):  
Barbora Sláviková ◽  
M. Miklošovičová ◽  
E. Illeková ◽  
V. Majerník ◽  
O. Šauša ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Pore Size ◽  
Positron Annihilation ◽  
Average Pore Size ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Scanning Calorimetry ◽  
Average Pore ◽  
Positron Annihilation Lifetime ◽  
Sio2 Aerogel

This work deals with the use of positron annihilation lifetime spectroscopy (PALS) for the study of hexadecane confined in SiO2 aerogel. The temperature dependencies of the o-Ps lifetime and intensity for this material were compared with values of hexadecane confined in silicagel with a similar average pore size. The results of differential scanning calorimetry (DSC) for both these materials will be discussed.

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