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Title: Discrete film thickness in polyacrylamide-CdS nanocomposite ultrathin films

Journal Article · · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
;  [1]
  1. Surface Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064 (India)

A nanocomposite of polyacrylamide, a water soluble polymer, and nanocrystalline CdS has been prepared using a chemical route. Transmission electron microscope observation shows that the particles are attached via the polymer coils. The reduction of viscosity for the composite, despite the increase in concentration, indicates a reduction of interchain entanglement between the composite coils. Ultrathin films were prepared from the nanocomposite and pure polyacrylamide using spin coating on a Si(100) substrate in the speed range of 500 to 5000 rpm. X-ray reflectivity studies of the pure polymer and composite films were carried out in vacuum. The thickness of the composite films varies nonmonotonically with spinning speed and is found to lie in discrete 'bands' of thickness separated by 'forbidden regions'. The power law behavior of the thickness with the spinning speed was also found to be different for the composite films in comparison to the polymer ones. A model has been proposed in terms of discrete numbers of layers composed of CdS-attached polymer coils to explain the phenomena.

OSTI ID:
20636852
Journal Information:
Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Vol. 70, Issue 5; Other Information: DOI: 10.1103/PhysRevE.70.051608; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-651X
Country of Publication:
United States
Language:
English