Abstract
Monodisperse polystyrene (PS) films with various thicknesses were spun-coated on silicon wafers with native oxide layer. Surface relaxation behavior in the PS films was studied as a function of thickness by lateral force microscopy (LFM). In the case of a thick PS film, a clear lateral force peak corresponding to surface αa-relaxation process of segmental motion was observed at a temperature much lower than the bulk glass transition temperature, Tg. As the film became thinner than 3-4 times the radius of gyration of an unperturbed consistent chain, the peak on lateral force vs temperature curve started to broaden out with decreasing thickness and eventually split into two peaks. The appearance temperature of the surface αa-relaxation peak was invariant with respect to the film thickness even in such an ultrathin state, meaning that surface Tg was insensitive to the thickness. On the other hand, the ultrathinning-induced relaxation process, called surface β-relaxation, was strongly dependent on the thickness in terms of relaxation temperature and apparent activation energy. Finally, possible origins of the surface β-relaxation process were proposed.
| Original language | English |
|---|---|
| Pages (from-to) | 4937-4943 |
| Number of pages | 7 |
| Journal | Macromolecules |
| Volume | 36 |
| Issue number | 13 |
| DOIs | |
| Publication status | Published - Jul 1 2003 |
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All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry
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Anomalous surface relaxation process in polystyrene ultrathin films. / Akabori, Kei Ichi; Tanaka, Keiji; Kajiyama, Tisato; Takahara, Atsushi.
In: Macromolecules, Vol. 36, No. 13, 01.07.2003, p. 4937-4943.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Anomalous surface relaxation process in polystyrene ultrathin films
AU - Akabori, Kei Ichi
AU - Tanaka, Keiji
AU - Kajiyama, Tisato
AU - Takahara, Atsushi
PY - 2003/7/1
Y1 - 2003/7/1
N2 - Monodisperse polystyrene (PS) films with various thicknesses were spun-coated on silicon wafers with native oxide layer. Surface relaxation behavior in the PS films was studied as a function of thickness by lateral force microscopy (LFM). In the case of a thick PS film, a clear lateral force peak corresponding to surface αa-relaxation process of segmental motion was observed at a temperature much lower than the bulk glass transition temperature, Tg. As the film became thinner than 3-4 times the radius of gyration of an unperturbed consistent chain, the peak on lateral force vs temperature curve started to broaden out with decreasing thickness and eventually split into two peaks. The appearance temperature of the surface αa-relaxation peak was invariant with respect to the film thickness even in such an ultrathin state, meaning that surface Tg was insensitive to the thickness. On the other hand, the ultrathinning-induced relaxation process, called surface β-relaxation, was strongly dependent on the thickness in terms of relaxation temperature and apparent activation energy. Finally, possible origins of the surface β-relaxation process were proposed.
AB - Monodisperse polystyrene (PS) films with various thicknesses were spun-coated on silicon wafers with native oxide layer. Surface relaxation behavior in the PS films was studied as a function of thickness by lateral force microscopy (LFM). In the case of a thick PS film, a clear lateral force peak corresponding to surface αa-relaxation process of segmental motion was observed at a temperature much lower than the bulk glass transition temperature, Tg. As the film became thinner than 3-4 times the radius of gyration of an unperturbed consistent chain, the peak on lateral force vs temperature curve started to broaden out with decreasing thickness and eventually split into two peaks. The appearance temperature of the surface αa-relaxation peak was invariant with respect to the film thickness even in such an ultrathin state, meaning that surface Tg was insensitive to the thickness. On the other hand, the ultrathinning-induced relaxation process, called surface β-relaxation, was strongly dependent on the thickness in terms of relaxation temperature and apparent activation energy. Finally, possible origins of the surface β-relaxation process were proposed.
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UR - http://www.scopus.com/inward/citedby.url?scp=0038119507&partnerID=8YFLogxK
U2 - 10.1021/ma034001y
DO - 10.1021/ma034001y
M3 - Article
AN - SCOPUS:0038119507
VL - 36
SP - 4937
EP - 4943
JO - Macromolecules
JF - Macromolecules
SN - 0024-9297
IS - 13
ER -