Polycondensation in liquid crystalline phases of nonionic surfactants. Kinetics and morphology

Guruswamy Kumaraswamy, Mohan N. Wadekar, Vikrant V. Agrawal, Renu Pasricha

Research output: Contribution to journalArticlepeer-review

Abstract

We have investigated acid-catalyzed polycondensation of alkoxysilane monomers in liquid crystalline phases of nonionic CnEm surfactants. The liquid crystalline phase is retained when the monomers polymerize. The high molecular weight molecules formed phase separate from the mesophase and are subsequently organized by it to form micron-sized particles. A variety of particle morphologies are formed by organization of the polymer particles in the mesophase. For condensation of dimethyldimethoxysilane (DMS, with trimethoxysilane, TMS as crosslinker) in hexagonal and lamellar phases, specific reaction conditions, viz. slow condensation kinetics and low crosslink density, give rod-like particles in hexagonal phases and sheet-like structures in lamellar phases. However, when higher acid concentrations are used, the reaction kinetics accelerates and irregular particles form. Irregular particles also form when the fraction of trifunctional crosslinker is increased, and finally complex flower-like structures form for condensation of trimethoxysilane in the hexagonal phase. The particle morphology formed is crucially dependent on the details of the polycondensation rate, crosslinker density and surfactant-monomer/oligomer interactions.

Original languageEnglish (US)
Pages (from-to)7961-7968
Number of pages8
JournalPolymer
Volume46
Issue number19 SPEC. ISS.
DOIs
StatePublished - Sep 8 2005

Keywords

  • Nonionic
  • Surfactant
  • Templated synthesis

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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