Incorporation of polyfluorenes into poly(lactic acid) films for sensor and optoelectronics applications

Abstract

Films of neat and plasticized biodegradable poly(lactic acid) (PLA) matrices containing anionic conjugated polyelectrolytes, poly[9,9-bis(4-phenoxybutylsulfonate)]fluorene-2,7-diyl-alt-arylenes, with 1,4-phenylene and 4,4 -p-terphenylene, respectively, as arylene groups or a neutral poly(9,9-dialkylfluorene) for comparison were prepared by solution casting. These films were characterized using differential scanning calorimetry, thermogravimetry, scanning electron microscopy and fluorescence spectroscopy. In addition, the effects of plasticizer on the thermal properties and the oxygen permeability of the PLA films were measured through the oxygen transmission rate. Results show that it is possible to obtain thin, optically transparent and luminescent films with potential in oxygen sensing, exhibiting good thermal and photochemical stability. At high polyelectrolyte content, evidence is found for phase separation and aggregate formation and it is no longer possible to obtain completely homogeneous films. The possibility of incorporating the cationic metal complex tris(2,2 -bipyridyl)ruthenium(II) into plasticized PLA films containing conjugated polyelectrolytes for dual-wavelength ratiometric luminescence sensing is also discussed.

Effects of Charge Density on Photophysics and Aggregation Behavior of Anionic Fluorene-Arylene Conjugated Polyelectrolytes

“…Conjugated polyelectrolytes (CPEs) have emerged as advanced materials, which combine the electronic, spectroscopic, and photophysical properties of conjugated organic polymers with the solubility in water and polar solvents of ionic compounds [ 1 , 2 , 3 ]. Their aqueous solubility makes them valuable as sensors of biological or chemical systems [ 4 , 5 , 6 , 7 , 8 , 9 ], whilst their ionic character provides the potential for use in optoelectronics [ 10 ], as charge injection or transport layers [ 11 ], in light emitting devices [ 12 ], or as solar concentrators [ 13 ]. In addition, as polyelectrolytes, they can self-assemble with oppositely charged species, such as surfactants, to build up complex multilayer structures with various potential materials applications [ 14 , 15 ].…”

Chain Length Dependent Excited-State Decay Processes of Diluted PF2/6 Solutions

“…The study of conjugated polymers (CPs), which can be considered as multichromophoric systems with the number of chromophores strongly depending on the chain length, and in particular the investigation of isolated CP chains with emphasis on the excited-state decay processes occurring in these systems, have attracted much attention over the past 2 decades. − Tuning of the photophysical properties of CPs has led to the development of new functional materials for optoelectronic applications. − Whereas in small π-conjugated organic molecules the excited state is often extended across the whole molecule, the situation in conjugated polymers is more complex. In CPs, the excitons are delocalized over a restricted range (the so-called effectively conjugated segment) along the conjugated π-electron system of the backbone.…”

Synthesis and Characterization of Poly(DL-lactide) Containing Fluorene Structures

“…These modified derivatives can undergo addition or condensation reactions with other monomers, leading to the formation of diverse polymer materials with applications in optoelectronics, electronics, and automotive industries [39][40][41][42]. Previous studies conducted by various researchers have investigated the incorporation of bisphenol fluorene derivatives into PLA and explored their impact on the thermal properties of the resulting materials [43,44].…”