Photoluminescence of 2,7-Poly(9,9-dialkylfluorene-co-fluorenone) Nanoparticles: Effect of Particle Size and Inert Polymer Addition

• Published in: Langmuir 2010-09, Vol.26 (18), p.14437-14442
• Main Authors: Pras, O, Chaussy, D, Stephan, O, Rharbi, Y, Piette, P, Beneventi, D
• Format: Article
• Language: English
• Subjects: Cellulose - analogs & derivatives; Cellulose - chemistry; Chemistry; Colloidal state and disperse state; Colloids: Surfactants and Self-Assembly, Dispersions, Emulsions, Foams; Exact sciences and technology; Fluorenes - chemistry; General and physical chemistry; Hydrophobic and Hydrophilic Interactions; Luminescent Measurements; Nanoparticles - chemistry; Particle Size; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Polymers - chemistry; Suspensions; Time Factors
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la1011742

Stable nanoparticle dispersions of 2,7-poly(9,9-dialkylfluorene-co-fluorenone) (PFFO) and of PFFO/cellulose acetate butyrate (CAB) mixtures with particle size ranging between 5 and 500 nm were prepared by miniemulsification in the presence of a cationic surfactant. Photoluminescence spectra of nanoparticle dispersions showed that the decrease of particle size and of the PFFO/CAB mass ratio induced the progressive suppression of the PFFO excimer emission band at 535 nm. This behavior was associated with the limited ordered structure and π-stacking arrangement of PFFO molecules when confined within nanoparticles smaller than 150 nm or in the presence of CAB molecules. All nanoparticle dispersions displayed high dimensional stability; however, the relative intensity of the excimer emission band increased upon aging reflecting excimer formation due to the high mobility of PFFO chains (T g −20 °C) or fluorene moiety oxidation.