New asymmetric substitution of phthalocyanines: Derivatives designed for deposition as Langmuir-Blodgett films

N. B. McKeown, M. J. Cook*, A. J. Thomson, K. J. Harrison, M. F. Daniel, R. M. Richardson, S. J. Roser

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

66 Citations (Scopus)

Abstract

The monolayer and deposition behaviours of 1,4,8,11,15,18-hexa-alkyl-22,25-bis (carboxyethyl)phthalocyanines and 1,4,8,11,15,18,22,25-octa-alkylphthalocyanines have been compared. Compounds in the former series show better monolayer behaviour at the air-water interface than those in the latter series, which form rigid films that cannot be deposited onto substrates. Examples of the first series are excellent for fabrication as Langmuir-Blodgett (LB) films, giving evenly deposited well-ordered bilayer assemblies by Y-type deposition. The effect of temperature on an LB film of one of the compounds has been monitored using polarized absorption spectroscopy and low-angle X-ray diffraction. Up to 50°C the film undergoes some initial reorganization of what is presumed to be a metastable state formed during initial deposition. The molecular structure undergoes a more substantial transition at 127.5°C over a 0.5°C temperature range to a modified film in which adjacent molecules lose translational non-equivalence. Furthermore, there is a reduction in the bilayer thickness from 41 to 36 Å. This process is irreversible as judged by UV-visible spectroscopy.

Original languageEnglish
Pages (from-to)469-478
Number of pages10
JournalThin Solid Films
Volume159
Issue number1-2
DOIs
Publication statusPublished - 1 Jan 1988

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