Free volume and density gradients of amorphous polymer surfaces as determined by use of a pulsed low-energy positron lifetime beam and PVT data
(2004) In Macromolecules 37(11). p.4201-4210- Abstract
- Density gradient widths at the polymer-vacuum surfaces of poly(methyl methacrylate), styrene-co-acrylonitrile, and styrene-co-maleic anhydride were quantified to 2, 5, and 4 rim, respectively, by use of a pulsed low-energy positron lifetime beam and to approximately 1.5 nm for all three polymers on the basis of theoretical predictions from pressure-volume-temperature (PVT) data, making use of the Cahn-Hilliard theory of inhomogeneous systems in conjunction with the Sanchez-Lacombe lattice fluid theory. Excellent agreement between the two methods was found for the homopolymer, whereas for the copolymers, the former method gave larger density gradient widths, a result attributed to the surface orientation of the less polar polymer segments,... (More)
- Density gradient widths at the polymer-vacuum surfaces of poly(methyl methacrylate), styrene-co-acrylonitrile, and styrene-co-maleic anhydride were quantified to 2, 5, and 4 rim, respectively, by use of a pulsed low-energy positron lifetime beam and to approximately 1.5 nm for all three polymers on the basis of theoretical predictions from pressure-volume-temperature (PVT) data, making use of the Cahn-Hilliard theory of inhomogeneous systems in conjunction with the Sanchez-Lacombe lattice fluid theory. Excellent agreement between the two methods was found for the homopolymer, whereas for the copolymers, the former method gave larger density gradient widths, a result attributed to the surface orientation of the less polar polymer segments, which the theoretical predictions did not take into account. As has been previously proposed, the discrepancy between the depth ranges of the surface effects on density and the glass transition temperature (T-g) is suggested to result from a coupling between the dynamics of adjoining polymer segments, canceling a direct relationship between local density profile rho(z) and local T-g(z) as a function of distance z from the free surface. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/139521
- author
- Algers, John LU ; Suzuki, R ; Ohdaira, T and Maurer, Frans LU
- organization
- publishing date
- 2004
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Macromolecules
- volume
- 37
- issue
- 11
- pages
- 4201 - 4210
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000221688600037
- scopus:2942592316
- ISSN
- 0024-9297
- DOI
- 10.1021/ma0359335
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Polymer and Materials Chemistry (LTH) (011001041)
- id
- a77fd69e-7954-49f8-b002-053dfd763e58 (old id 139521)
- date added to LUP
- 2016-04-01 12:05:13
- date last changed
- 2022-04-13 05:54:19
@article{a77fd69e-7954-49f8-b002-053dfd763e58,
abstract = {{Density gradient widths at the polymer-vacuum surfaces of poly(methyl methacrylate), styrene-co-acrylonitrile, and styrene-co-maleic anhydride were quantified to 2, 5, and 4 rim, respectively, by use of a pulsed low-energy positron lifetime beam and to approximately 1.5 nm for all three polymers on the basis of theoretical predictions from pressure-volume-temperature (PVT) data, making use of the Cahn-Hilliard theory of inhomogeneous systems in conjunction with the Sanchez-Lacombe lattice fluid theory. Excellent agreement between the two methods was found for the homopolymer, whereas for the copolymers, the former method gave larger density gradient widths, a result attributed to the surface orientation of the less polar polymer segments, which the theoretical predictions did not take into account. As has been previously proposed, the discrepancy between the depth ranges of the surface effects on density and the glass transition temperature (T-g) is suggested to result from a coupling between the dynamics of adjoining polymer segments, canceling a direct relationship between local density profile rho(z) and local T-g(z) as a function of distance z from the free surface.}},
author = {{Algers, John and Suzuki, R and Ohdaira, T and Maurer, Frans}},
issn = {{0024-9297}},
language = {{eng}},
number = {{11}},
pages = {{4201--4210}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Macromolecules}},
title = {{Free volume and density gradients of amorphous polymer surfaces as determined by use of a pulsed low-energy positron lifetime beam and PVT data}},
url = {{http://dx.doi.org/10.1021/ma0359335}},
doi = {{10.1021/ma0359335}},
volume = {{37}},
year = {{2004}},
}