Well-defined novel fluorene-containing polymers: synthesis, fluorescent properties, and micellar nanoparticles.

We report the synthesis of a new monomer, 9,9-diethylfluoren-2-yl methyl methacrylate (FMMA) and its controlled reversible addition-fragmentation chain transfer (RAFT) homopolymerization to give PFMMA with narrow polydispersity indices (PDIs). The corresponding copolymerization with 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) also gave well-defined block and random copolymers with controlled molecular weights and narrow PDIs. Their thermal behavior, UV-Vis absorption, and photoluminescent properties were studied.

Investigation of macrocyclic polymers as artificial light harvesters: subpicosecond energy transfer in poly(9,9-dimethyl-2-vinylfluorene).

The spectroscopy and dynamics of a novel molecular architecture that mimics natural light harvesting have been characterized. The deployment of 9,9-dimethyl-2-fluorenyl (DMF) chromophores in atactic macrocyclic poly(9,9-dimethyl-2-vinylfluorene) is similar to that in the light harvesting antenna LH2 of the purple photosynthetic bacteria. A variety of spectroscopic probes are used to study the dynamics in these novel polymer systems.

Block copolymer-like self-assembly of fluorocarbon end-functionalized polystyrene and polybutylmethacrylate.

We demonstrate the self-assembly through fluorophilic interactions of a blend of perfluorocarbon (RF) end-functionalized polystyrene and the corresponding RF-polybutylmethacrylate into optically transparent materials that retain domain characteristics typical of the component polymers but show well-defined lamellar nanostructured morphologies that qualitatively resemble that of the corresponding block copolymers.

DFT based Monte Carlo simulations of poly(9,9-dialkylfluorene-2,7-diyl) polymers in solution.

The dilute solution properties of poly(9,9-dihexylfluorene-2,7-diyl) (PDHF) were studied by coupled SEC/light scattering and MALDI-TOF over a large molecular weight (MW) span ranging from PDHF oligomers (1-8-mer) to high MW polymer. The results were compared with Monte Carlo simulations based on realistic PDHF models obtained from X-ray data and density functional theory (DFT) calculations and with a DFT based Kratky-Porod-Benoit-Doty (KPBD) worm-like chain. The simulations called "selective random walk" (SRW) and the corresponding "selective self-avoiding random walk" (SSAW) explicitly take into account the rotationally labile bonds between the fluorene units in that four distinct torsion angles (+/-37.

Percutaneous fiber-optic sensor for chronic glucose monitoring in vivo.

We are developing a family of fiber-optic sensors called Sencils (sensory cilia), which are disposable, minimally invasive, and can provide in vivo monitoring of various analytes for several weeks. The key element is a percutaneous optical fiber that permits reliable spectroscopic measurement of chemical reactions in a nano-engineered polymeric matrix attached to the implanted end of the fiber. This paper describes its first application to measure interstitial glucose based on changes in fluorescence resonance energy transfer (FRET) between fluorophores bound to betacyclodextrin and Concanavalin A (Con A) in a polyethylene glycol (PEG) matrix.

Senciltrade mark project: development of a percutaneous optical biosensor.

We describe the design, fabrication method, biocompatibility test results, and first application of the novel chemical sensor technology that is under development. The sensor is designed to be minimally invasive, disposable and easily readable to make frequent measurements of various analytes in vivo over a period of 1-3 months. It uses photonic sensing of a chemical reaction that occurs in a polymer matrix bound to the internal end of a chronically implanted percutaneous optical fiber.

Phosphorescence quenching by conjugated polymers.

Energy transfer between phosphors and conjugated polymers was investigated using a fluorene trimer (F3) as a model conjugated material. The phosphors studied were bis-cyclometalated iridium complexes (FP, PPY, BT, PQ, and BTP), with triplet energies of 2.6, 2.