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Titolo:
Scaling aspects of the kinetics of thermally induced phase separation in bisphenol A polycarbonate/poly(methyl methacrylate) blends
Autore:
Viville, P; Biscarini, F; Bredas, JL; Lazzaroni, R;
Indirizzi:
Univ Mons, Ctr Rech Elect & Photon Mol, Serv Chim Mat Nouveaux, B-7000 Mons, Belgium Univ Mons Mons Belgium B-7000 rv Chim Mat Nouveaux, B-7000 Mons, Belgium CNR, Ist Spettroscopia Mol, I-40129 Bologna, Italy CNR Bologna Italy I-40129 Ist Spettroscopia Mol, I-40129 Bologna, Italy Univ Arizona, Dept Chem, Tucson, AZ 85721 USA Univ Arizona Tucson AZ USA 85721 Arizona, Dept Chem, Tucson, AZ 85721 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 31, volume: 105, anno: 2001,
pagine: 7499 - 7507
SICI:
1520-6106(20010809)105:31<7499:SAOTKO>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
SURFACE DEFORMATION MODES; ATOMIC-FORCE MICROSCOPY; POLY(METHYL METHACRYLATE); POLYMER BLEND; A POLYCARBONATE; THIN-FILMS; MORPHOLOGY; BEHAVIOR; DECOMPOSITION; MISCIBILITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Viville, P Univ Mons, Ctr Rech Elect & Photon Mol, Serv Chim Mat Nouveaux,20 Pl Parc, B-7000 Mons, Belgium Univ Mons 20 Pl Parc Mons Belgium B-7000 B-7000 Mons, Belgium
Citazione:
P. Viville et al., "Scaling aspects of the kinetics of thermally induced phase separation in bisphenol A polycarbonate/poly(methyl methacrylate) blends", J PHYS CH B, 105(31), 2001, pp. 7499-7507

Abstract

Phase separation in blends of bisphenol A polycarbonate and poly(methyl methacrylate), PC/PMMA, is investigated on the microscopic scale by means of atomic force microscopy (AFM). This technique allows the visualization of the early stages of phase separation with greater accuracy, relative to optical techniques. In comparison to previous data, the AFM-determined demixionvs composition curve appears to be shifted to lower temperatures. Startingfrom homogeneous thin films, we then follow the thermally induced spinodaldecomposition process of 50/50 blends and characterize the morphological changes as a function of demixion time and annealing temperature. We presenta quantitative investigation of the growth of the dispersed phase, based on a statistical power spectral density analysis of the AFM data. The interest of this method is to provide information on the growth mechanism, by establishing the scaling relationships between the topographic roughness (which is due to phase separation), the length scale of observation, and the annealing time. In the present case, the phase separation process appears to follow the Kardar-Parisi-Zhang universality class of growth, in which the density is not a conserved quantity. The corresponding morphology is accordingly marked by a clear topographic discontinuity between the PMMA-rich domains and the PC-rich matrix. We also observe that, at temperatures exceeding 220 degreesC, the late stages of the spinodal decomposition process are strongly affected by the occurrence of chemical reactions between PC and PMMA,which slow the growth rate of the dispersed phase and the surface roughening.

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Documento generato il 08/07/20 alle ore 06:53:27