Liquid phase deposition of titania onto nanostructured poly-p-xylylene thin films

Niranjan Malvadkar, Walter J. Dressick, Melik C. Demirel

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

We describe a simple, solution-based, two-step process for the fabrication of titania-parylene composite films as a prerequisite for their evaluation as materials for bioimplant applications. In the first step, a ligand capable of binding titania, such as phenylphosphonic acid, is physisorbed onto a nanostructured poly-p-xylylene thin film previously prepared via surface-promoted oblique angle polymerization of radicals formed during vapor-phase pyrolysis of [2.2]-p-cyclophanes. The adsorbed ligand templates conformal growth of titania on the polymer surface in the second step via a liquid phase deposition process involving the controlled hydrolysis of (NH 4) 2TiF 6 in the presence of H 3BO 3 in pH 2.88 aqueous solution at ∼50 °C. SEM and AFM analyses support a deposition mechanism that includes direct growth of titania on the ligand-impregnated parylene surface, as well as incorporation of titania nanoparticles nucleated in solution into the growing film. XPS and XRD results show that the as-deposited titania contains both amorphous and nanocrystalline anatase phases, with the latter readily consolidated by annealing at ∼200 °C without destruction of the underlying parylene polymer. Titania adhesion can be tuned by proper choice of the ligand, with ligands such as phenylphosphonic acid that strongly bind to titanium dioxide leading to deposition of titania films that pass the Scotch ® tape adhesion test.

Original languageEnglish (US)
Pages (from-to)4796-4804
Number of pages9
JournalJournal of Materials Chemistry
Volume19
Issue number27
DOIs
StatePublished - Jul 9 2009

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Chemistry

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