Reversible flocculation of silica across the phase boundary of poly(vinyl caprolactam) in aqueous solution

Q. Qiu, Brian Anthony Pethica, P. Somasundaran

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The colloid stability of silica dispersions in water in the presence of poly(vinyl caprolactam) (PVCAP) has been studied below and above the lower consolute temperature (LCT) of its solutions. The dispersion sediments slowly without PVCAP in the temperature range studied (26-40°C) or with PVCAP below the LCT (∼30°C). In contrast, with PVCAP above the LCT, rapid flocculation occurs at acid pH, with redispersal on cooling. Reversible flocculation is also obtained above the LCT by cycling the pH from alkaline to acid and back. The flocculation observed above the LCT may also be regarded as heterocoagulation between the silica particles and the aggregates of the polymer.

Original languageEnglish (US)
Pages (from-to)12096-12099
Number of pages4
JournalLangmuir
Volume21
Issue number26
DOIs
StatePublished - Dec 20 2005

All Science Journal Classification (ASJC) codes

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

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