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Volumn 119, Issue 20, 1997, Pages 4698-4711

Synthesis of crystalline, nanometer-scale, -(CH2)(x)- clusters and films on gold surfaces

Author keywords

[No Author keywords available]

Indexed keywords

DIAZOMETHANE; FREE RADICAL; GOLD; HYDROCARBON; METHYL GROUP;

EID: 0030984988     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja964395r     Document Type: Article
Times cited : (39)

References (81)
  • 29
    • 0003774488 scopus 로고
    • J. Wiley and Sons: New York
    • Typical polyethylene refractive index values in the optical region are 1.49 and 1.52 for amorphous and crystalline materials [see: Polymer Handbook, 2nd ed.; Immergut, E. H., Brandrup, J., Eds.; J. Wiley and Sons: New York, 1975; with further reference to: Bryant, W. M. D. J. Polym. Sci. 1947 2, 556].
    • (1975) Polymer Handbook, 2nd Ed.
    • Immergut, E.H.1    Brandrup, J.2
  • 30
    • 1842383921 scopus 로고
    • Typical polyethylene refractive index values in the optical region are 1.49 and 1.52 for amorphous and crystalline materials [see: Polymer Handbook, 2nd ed.; Immergut, E. H., Brandrup, J., Eds.; J. Wiley and Sons: New York, 1975; with further reference to: Bryant, W. M. D. J. Polym. Sci. 1947 2, 556].
    • (1947) J. Polym. Sci. , vol.2 , pp. 556
    • Bryant, W.M.D.1
  • 31
    • 0030567273 scopus 로고    scopus 로고
    • A recent study on model heterogeneous surfaces consisting of alternating hydrophilic and hydrophobic strips reveals that these systems are characterized by a contortion of the three-phase contact line for liquid drops present on the surface. The advancing and receding contact angles were lower by 2-10° when measured with the strips normal to the contact line than those measured with the strips tangential to the three-phase line. See, Drelich, J.; Wilbur, J. L.; Miller, J. D.; Whitesides, G. M. Langmuir 1996, 12, 1913-22.
    • (1996) Langmuir , vol.12 , pp. 1913-1922
    • Drelich, J.1    Wilbur, J.L.2    Miller, J.D.3    Whitesides, G.M.4
  • 37
    • 9344260686 scopus 로고
    • -1 (attributed to the symmetric methyl bending modes. Snyder, R. G. J. Mol. Spectrosc. 1961, 7, 116-144).
    • (1961) J. Mol. Spectrosc. , vol.7 , pp. 116-144
    • Snyder, R.G.1
  • 43
    • 0012573157 scopus 로고
    • -1. The existence of the monoclinic form has been reported in the case of polymethylene under conditions of stress, such as shaken preparations of polymethylene crystals (Kikuchi, Y.; Krimm, S. J. Macromol. Sci. Phys. 1970, B(4), 461-72) and cold drawing of polyethylene ( Schmidt, P. G. J. Polym. Sci. 1963, 1A, 1271).
    • (1962) J. Mol. Spectrosc. , vol.8 , pp. 383
    • Holland, R.F.1    Nielsen, J.R.2
  • 44
    • 0017516573 scopus 로고
    • -1. The existence of the monoclinic form has been reported in the case of polymethylene under conditions of stress, such as shaken preparations of polymethylene crystals (Kikuchi, Y.; Krimm, S. J. Macromol. Sci. Phys. 1970, B(4), 461-72) and cold drawing of polyethylene ( Schmidt, P. G. J. Polym. Sci. 1963, 1A, 1271).
    • (1977) J. Polym. Sci. Polym. Phys. , vol.15 , pp. 1237-1249
    • Painter, P.C.1    Havens, J.2    Hart, W.W.3    Koenig, J.L.4
  • 45
    • 84951407569 scopus 로고
    • -1. The existence of the monoclinic form has been reported in the case of polymethylene under conditions of stress, such as shaken preparations of polymethylene crystals (Kikuchi, Y.; Krimm, S. J. Macromol. Sci. Phys. 1970, B(4), 461-72) and cold drawing of polyethylene ( Schmidt, P. G. J. Polym. Sci. 1963, 1A, 1271).
    • (1970) J. Macromol. Sci. Phys. , vol.B , Issue.4 , pp. 461-472
    • Kikuchi, Y.1    Krimm, S.2
  • 46
    • 0001206490 scopus 로고
    • -1. The existence of the monoclinic form has been reported in the case of polymethylene under conditions of stress, such as shaken preparations of polymethylene crystals (Kikuchi, Y.; Krimm, S. J. Macromol. Sci. Phys. 1970, B(4), 461-72) and cold drawing of polyethylene ( Schmidt, P. G. J. Polym. Sci. 1963, 1A, 1271).
    • (1963) J. Polym. Sci. , vol.1 A , pp. 1271
    • Schmidt, P.G.1
  • 51
    • 1842342401 scopus 로고    scopus 로고
    • note
    • 3 groups is statistically neglible. However, these materials exhibit somewhat different band shapes for some important peaks, e.g., C-H stretching, than our PM films, and the optical functions were not considered as accurate models for our purposes. The second, and perhaps most important, difficulty arises from the complicated morphologies of the films. The thinner films consist of isolated clusters embedded to some extent within the depths of gold defect regions whereas the thicker films, while nominally continuous, most likely exhibit considerable void contents. Optical response simulations for these types of morpholgies require the use of effective medium approximations. In the present case, the accuracy of the simulations will be subject to the inherent uncertainties in the film structures with respect to the composition of gold, air, and PM. Further rigorous studies of these chain orientation calculations are in progress and will be reported elsewhere.
  • 53
    • 1842318406 scopus 로고    scopus 로고
    • note
    • In addition to incorporating the discontinuous character of the film in the ellipsometric model, a more rigorous treatment should consider the possibility that the chains may be uniformly aligned, likely parallel to the substrate, thus giving rise to film anisotropy. On this basis the film optical functions should be desribed in terms of second rank tensors. We have performed calculations based on an anisotropic PM-void composite model, which incorporates the known birefringence of alkyl chains, and find that the ellipsometric thicknesses are even lower by ≃10% than from the isotropic composite model.
  • 55
    • 1842348179 scopus 로고    scopus 로고
    • note
    • More sophisticated film models in which corrections were made for variable recoil trajectories from the nanometer-sized PM clusters did not result in appreciable changes in the calculated thicknesses. On average, the recoiling ions will traverse through various regions of dense PM, gold (especially in the thinner films where clusters can nucleate in depressed gold defects), and void regions. Since the stopping power of each of these regions differs significantly there will be a skewing of the energy-yield spectrum as a function of the actual film morphology. In general, in view of the low-energy resolution of the detector, equivalent to ≃60-80 nm depth resolution, significant errors do not arise from variable morphologies in PM films of less than 30-40 nm thicknesses. The effect of variable void fraction was simulated by assuming the recoil spectrum to be composed of contributions from isolated microscopic slabs of differing thicknesses. Simulations performed with use of the RUMP package showed almost negligible changes in total energy spread at the detector for a variety of slab morphologies, and the recoil ion yields essentially remain linear with the average film thicknesses.
  • 63
    • 1842385926 scopus 로고    scopus 로고
    • note
    • 3 group appears as a result of chain termination via reaction 3, these observations imply that the degree of polymerization may be lower near the Au/PM interface.
  • 70
    • 0348189724 scopus 로고    scopus 로고
    • For example, see: Bent, B. E. Chem. Rev. 1996, 96, 1361-1390.
    • (1996) Chem. Rev. , vol.96 , pp. 1361-1390
    • Bent, B.E.1
  • 76
    • 1842396675 scopus 로고    scopus 로고
    • Unpublished results
    • Preliminary high-resolution AFM images of films in the intermedate stages of growth show features on the {111} terraces which appear to be single chains. [Seshadri, K. Allara, D. L. Unpublished results.]
    • Seshadri, K.1    Allara, D.L.2
  • 79
    • 0038344149 scopus 로고
    • x reactions on Cu are near zero [Shustorovich, E. Catal. Lett. 1990, 7, 107-118]. Since this will hold for Au as well, the rate of reaction 10 will be diffusion limited.
    • (1990) Catal. Lett. , vol.7 , pp. 107-118
    • Shustorovich, E.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.