Langmuir-blodgett-kuhn and self-assembled films of asymmetrically substituted poly(paraphenylene)

F. Fitrilawati, R. Renu, C. Baskar, L. G. Xu, H. S.O. Chan, S. Valiyaveettil, K. Tamada, W. Knoll

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12 Citations (Scopus)

Abstract

Asymmetrically substituted poly(paraphenylene) (PhPPP) with hydrophilic and hydrophobic side chains was investigated. The polymer behavior at the air-water interface was studied on the basis of surface pressure-area (π-A) isotherms and compression/expansion hysteresis measurements. PhPPP can form stable monolayers with an area per repeat unit of A = 0.20 ± 0.02 nm2 and a collapse pressure in the range of π = 25 mN/m. Then, Langmuir-Blodgett-Kuhn (LBK) films of PhPPP were prepared by horizontally and vertically transferring the Langmuir monolayers onto hydrophilic solid substrates at π = 12 mN/m. Cross-section analysis of the AFM tapping-mode topography images of a single transferred monolayer reveals a thickness of d0 = 0.9 ± 0.1 nm. Taking into account the obtained monolayer thickness, curvefitting calculations of angular scan data of LB monolayers measured using surface plasmon resonance (SPR) spectroscopy lead to a value for the refractive index of n = 1.78 ± 0.02 at λ = 632.8 nm. Next, the spontaneous formation of a PhPPP monolayer by adsorption from solution was studied ex situ by atomic force microscopy and UV-vis spectroscopy and in situ by using SPR spectroscopy. Stable self-assembled monolayers of PhPPP can be formed on hydrophilic surfaces with a thickness similar to that of the monolayer obtained using the LB method. The characterization results confirmed the amphiphilic character and the self-assembly properties of PhPPP, as well as the possibility of preparing homogeneous monolayer and multilayer films.

Original languageEnglish
Pages (from-to)12146-12152
Number of pages7
JournalLangmuir
Volume21
Issue number26
DOIs
Publication statusPublished - Dec 20 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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