Surfactant free fabrication of polymeric nanoparticles by combined liquid-liquid phase separation and solvent/nonsolvent mixing technology

J. Y. Xiong*, X. Y. Liu, P. D. Sawant, S. B. Chen, Tai-Shung Chung, K. P. Pramoda

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

It is generally agreed that, in most cases, surfactants are required to obtain stable polymeric nanoparticle dispersions. Here, we report a method which can be used to produce surfactant free yet stable polymeric nanoparticle dispersions. This method is based on explored mechanism of selective solvation of nanoparticles and EPD (electron pair donor)/EPA (electron pair acceptor) complexes formed among solvent and nonsolvent molecules. Using polyimide P84 (copolyimide 3,3 4,4-benzophenone tetracarboxylic dianhydride and 80%methylphenylenediamine+20%methylenedianiline) as the model polymer, this mechanism was realized through a combined liquid-liquid phase separation and solvent/nonsolvent mixing technology. Surfactant-free polyimide nanoparticles (<100nm) were produced. Experimental details and principles of this technology were given based on the ternary diffusion, the liquid-liquid phase separation and the advanced nucleation and growth theory. Two types of methods [denoted as the forward titration method and the backward titration (BT) method] were examined. It was found that the BT method is extremely helpful to prepare polyimide nanoparticles (<100nm). As another important aspect, explored stabilization mechanism of the resultant nanoparticle dispersions was supported by the comparative experiments, implying that selective solvation of nanoparticles and EPD/EPA complexes may play key roles in stabilization.

Original languageEnglish (US)
Pages (from-to)12626-12631
Number of pages6
JournalJournal of Chemical Physics
Volume121
Issue number24
DOIs
StatePublished - Dec 22 2004

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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