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Volumn 41, Issue 20, 2008, Pages 7729-7743

Modeling dielectric relaxation in polymer glass simulations: dynamics in the bulk and in supported polymer films

Author keywords

[No Author keywords available]

Indexed keywords

ABS RESINS; ARSENIC; CAPACITANCE; CAPACITORS; DIELECTRIC DEVICES; DIELECTRIC RELAXATION; DYNAMICS; ELECTRIC EQUIPMENT; GLASS; GLASS TRANSITION; MOLECULAR DYNAMICS; POLYMER MELTS; POLYMERS; QUANTUM CHEMISTRY;

EID: 55649113123     PISSN: 00249297     EISSN: None     Source Type: Journal    
DOI: 10.1021/ma800694v     Document Type: Article
Times cited : (59)

References (107)
  • 34
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    • 51
    • 51
  • 75
    • 55649118809 scopus 로고    scopus 로고
    • The reason for why capping polymer films with an aluminum layer appears not to suppress free surface effects is not fully understood. A possible explanation could be that aluminum just coats the polymer surface during the evaporation process, thus preserving the sharp polymer-vacuum interface initially present.13
    • 13
  • 76
    • 25544460831 scopus 로고    scopus 로고
    • Kremer, F, Schönhals, A, Eds, Springer: Berlin
    • Schönhals, A. In Broadband Dielectric Spectroscopy; Kremer, F., Schönhals, A., Eds.; Springer: Berlin, 2003; pp 225-293.
    • (2003) Broadband Dielectric Spectroscopy , pp. 225-293
    • Schönhals, A.1
  • 87
    • 0004024743 scopus 로고    scopus 로고
    • Kremer, F, Schönhals, A, Eds, Springer: Berlin
    • Broadband Dielectric Spectroscopy; Kremer, F., Schönhals, A., Eds.; Springer: Berlin, 2003.
    • (2003) Broadband Dielectric Spectroscopy
  • 91
    • 55649111742 scopus 로고    scopus 로고
    • The low value of the strength index D ≈ 2.5 suggests that our polymer model is fairly fragile,90,102 as typically found for many polymeric glass-formers.103 However, a caveat should be mentioned here. Our strength index is determined from high-T data where the curvature of the relaxation time in an Arrhenius plot is fairly pronounced. Thus, we may expect D to change, i.e, to increase, if the simulations could be extended to much lower T
    • 103 However, a caveat should be mentioned here. Our strength index is determined from high-T data where the curvature of the relaxation time in an Arrhenius plot is fairly pronounced. Thus, we may expect D to change, i.e., to increase, if the simulations could be extended to much lower T.
  • 97
    • 55649114558 scopus 로고    scopus 로고
    • Equivalent circuit models involving systems of capacitors are commonly employed in the interpretation of dielectric properties of inhomogeneous systems having a layered structure with true interfaces (see e.g. Chapter 13 of ref 87 or ref 104, In the context of glass-forming polymer films, the idea of associating layers of the film, which are not separated by true interfaces, with ideal capacitors (i.e, with zero resistances at the electrodes) is presumably correctly attributed to ref 53. The assumption of ideal capacitors is justified because contributions to dielectric spectra from the resistance at the top and bottom electrodes can be removed by a substration procedure cf. refs 21 and 28, and there is of course no resistance between the layers inside the film as the layers are not separated by true polymer-electrode interfaces
    • Equivalent circuit models involving systems of capacitors are commonly employed in the interpretation of dielectric properties of inhomogeneous systems having a layered structure with true interfaces (see e.g. Chapter 13 of ref 87 or ref 104). In the context of glass-forming polymer films, the idea of associating layers of the film, which are not separated by true interfaces, with ideal capacitors (i.e., with zero resistances at the electrodes) is presumably correctly attributed to ref 53. The assumption of ideal capacitors is justified because contributions to dielectric spectra from the resistance at the top and bottom electrodes can be removed by a substration procedure (cf. refs 21 and 28), and there is of course no resistance between the layers inside the film as the layers are not separated by true polymer-electrode interfaces.
  • 98
    • 55649106067 scopus 로고    scopus 로고
    • ∞ ≃ 2.5.
    • ∞ ≃ 2.5.
  • 101
    • 55649116791 scopus 로고    scopus 로고
    • The smoothness of this crossover seems hard to reconcile with a layer model, an often invoked interpretation for the relaxation of confined glass-forming liquids (see e.g. refs 58, 59, 106, and 107). This model assumes the coexistence of layers-typically one or two interfacial layers and an inner layei-with distinct mobilities (see e.g. ref 26 for a topical discussion of such models).
    • The smoothness of this crossover seems hard to reconcile with a layer model, an often invoked interpretation for the relaxation of confined glass-forming liquids (see e.g. refs 58, 59, 106, and 107). This model assumes the coexistence of layers-typically one or two interfacial layers and an inner layei-with distinct mobilities (see e.g. ref 26 for a topical discussion of such models).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.