Fluorene polymers Poly

Some authors have suggested the use of fluorene polymers for this kind of chromatography. Fluorinated polymers have attracted attention due to their unique adsorption properties. Polytetrafluoroethylene (PTFE) is antiadhesive, thus adsorption of hydrophobic as well as hydrophilic molecules is low. Such adsorbents possess extremely low adsorption activity and nonspecific sorption towards many compounds [109 111]. Fluorene polymers as sorbents were first suggested by Hjerten [112] in 1978 and were tested by desalting and concentration of tRN A [113]. Recently Williams et al. [114] presented a new fluorocarbon sorbent (Poly F Column, Du Pont, USA) for reversed-phase HPLC of peptides and proteins. The sorbent has 20 pm in diameter particles (pore size 30 nm, specific surface area 5 m2/g) and withstands pressure of eluent up to 135 bar. There is no limitation of pH range, however, low specific area and capacity (1.1 mg tRNA/g) and relatively low limits of working pressure do not allow the use of this sorbent for preparative chromatography. 

Rothe C, Guentner R, Scherf U, Monkman AP (2001) Trap influenced properties of the delayed luminescence in thin solid films of the conjugated polymer poly(9,9-di(ethylhexyl)fluorene). J Chem Phys 115(20) 9557—9562... 

Rothe C, Monkman A (2002) Dynamics and trap-depth distribution of triplet excited states in thin films of the light-emitting polymer poly(9,9-di(ethylhexyl)fluorene). Phys Rev B 65(7) 073201... 

Table 2.1 Abbreviations and full names for the four poly-fluorene polymers used in this chapter. 

PVK are critical in achieving high efficiency. While conjugated polymers, such as poly(fluorenes) and poly(phenylene-vinylenes), have been used extensively for fluorescence-based devices, they are not as useful for phosphorescence-based devices because they characteristically have low triplet energies. The triplet levels of most conjugated polymers are in the red to near-IR spectral region, and thus efficiently quench phosphorescence from dopants designed to emit in the visible part of the spectrum." ... 

Not only limited to the PFO polymer, another fluorene-based polymer poly(9,9-dioctylfluorene-a/t-benzothiadiazole) (F8BT) is also able to discrimi-nately wrap SWNTs with larger diameters such as a (15,4) tube." It has been suggested that a stable exciplex between poly[(9,9-dioctyl-fluorenyl-2,7-diyl)-co-(bithiophene)] (F8T2) and SWNTs exists, in which the energy level matching between SWNTs and fluorene-based polymers is responsible for the chirality selectivity. 

The conclusions drawn on the packing of PF chains can be extended to a parent polymer, poly (indenofluorene) (PIF see Figure 1.15). Indeed, thin deposits of n-octyl-substituted PIF (OPIF) show fibrillar patterns very similar to those observed for the other polymers in the series (Figure 1.23a). This suggests that the packing of the PIF chains is similar to that proposed for the poly(fluorene) chains. 

Pei, J., W.-L. Yu, W. Huang, and A.J. Heeger. 2000. The synthesis and characterization of an efficient green electroluminescent conjugated polymer Poly[2,7-his(4-hexylthienyl)-9,9-dihexyl-fluorene]. Chem Commun 1631-1632. 

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