Photoluminescence of 2,7-poly(9,9-dialkylfluorene-co-fluorenone) nanoparticles: effect of particle size and inert polymer addition.
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.
Pras
O
O
Laboratoire de Génie des Procédés Papetiers (LGP2), UMR 5518, 461 rue de la Papeterie, Du, BP. 65, 38402 Saint Martin d'Hères, France.
Chaussy
D
D
Stephan
O
O
Rharbi
Y
Y
Piette
P
P
Beneventi
D
D
D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D005449:Fluorenes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008163:Luminescent Measurements; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D013535:Suspensions; D013997:Time Factors
D005449:Fluorenes; D011108:Polymers; D013535:Suspensions; D002482:Cellulose