General Strategies for Nanoparticle Dispersion

• Published in: Science (American Association for the Advancement of Science) Vol. 311; no. 5768; pp. 1740 - 1743
• Main Authors: Mackay, Michael E, Tuteja, Anish, Duxbury, Phillip M, Hawker, Craig J, Van Horn, Brooke, Guan, Zhibin, Chen, Guanghui, Krishnan, R. S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 24.03.2006; The American Association for the Advancement of Science
• Subjects: Chemistry; Colloidal state and disperse state; Dispersion; Enthalpy; Exact sciences and technology; Fullerenes; General and physical chemistry; Gyration; Molecules; Monomers; Nanoparticles; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Polyethylenes; Polymer blends; Polymers; Solubility; Thermodynamics; Polyethylene; Transmission electron microscopy; Branched polymer; Nanoparticle; Fullerenes; Polymer; Radius of gyration; Thermodynamic stability; Styrene polymer; Liquid phase; Dispersion
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1122225

Traditionally the dispersion of particles in polymeric materials has proven difficult and frequently results in phase separation and agglomeration. We show that thermodynamically stable dispersion of nanoparticles into a polymeric liquid is enhanced for systems where the radius of gyration of the linear polymer is greater than the radius of the nanoparticle. Dispersed nanoparticles swell the linear polymer chains, resulting in a polymer radius of gyration that grows with the nanoparticle volume fraction. It is proposed that this entropically unfavorable process is offset by an enthalpy gain due to an increase in molecular contacts at dispersed nanoparticle surfaces as compared with the surfaces of phase-separated nanoparticles. Even when the dispersed state is thermodynamically stable, it may be inaccessible unless the correct processing strategy is adopted, which is particularly important for the case of fullerene dispersion into linear polymers.