Förster energy transfer studies of polyelectrolyte heterostructures containing conjugated polymers: A means to estimate layer interpénétration

Jeffery W. Baur, Michael F. Rubner, John R. Reynolds, Seungho Kirn

Research output: Contribution to journalArticlepeer-review

Abstract

Using a sequential adsorption process, thin film multilayer assemblies of polymers which photophysically interact via the Förster energy transfer mechanism have been fabricated and characterized in order to determine the level of interpénétration between layers. The assemblies consisted of layers of poly(phenylene vinylene) (PPV) which were separated from layers of a sulfonatopropoxy anion derivatized poly(p-phenylene) [(-)PPP] by nonconjugated polyelectrolyte spacer bilayers. The spacer bilayers were composed of poly(allylamine hydrochloride) (PAH) with a polyanion of either poly(acrylic acid) (PAA), polyCmethacrylic acid) (PMA), or poly(styrenesulfonate) (PSS). An estimate of the level of interpénétration of the layers was made for each type of spacer bilayer by correlating the relative amount of quenching of the (-)PPP photoluminescence with the measured total thickness of the spacer bilayer(s) utilizing a diffuse layer model which assumed a Gaussian distribution of polymer segments. Using this approach, the level of interpénétration for the assemblies with the PMA/PAH spacer bilayers was estimated to be between 15 and 53 A (1-2.5 bilayers). The heterostructure assembly which used spacer bilayers of PAA/PAH demonstrated that one sufficiently thick bilayer (> 57 A) could prevent the energy transfer from the (-)PPP to the PPV. The failure of the (-)PPP photoluminescence to be fully restored even with eight spacer bilayers (>53 A) for the assemblies containing PSS/PAH spacer bilayers indicated that, for the processing conditions used, significant layer mixing was obtained. Overall, this work demonstrated that nonradiative energy transfer offers a valuable tool for probing the internal structure of sequentially adsorbed polyelectrolyte films and that the level of interpetration appears to be dependent upon the system being examined.

Original languageEnglish (US)
Pages (from-to)6460-6469
Number of pages10
JournalLangmuir
Volume15
Issue number19
DOIs
StatePublished - Sep 14 1999
Externally publishedYes

ASJC Scopus subject areas

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

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