Effects of commercial non-ionic alkyl oxyethylene and ionic biocompatible arginine-based surfactants on the photophysical behaviour of several poly(fluorene-1,4-phenylene)s

Abstract In this paper, the interaction between three water soluble conjugated polymers: sodium poly{9,9-bis[(4-butylsulfonate)phenoxy]-2,7-fluorene- alt -1,4-phenylene} (PBS-PFP), poly{9,9-bis[(6′-N,N,N-trimethylammonium) hexyl]-2,7-fluorene- alt -1,4-phenylene} dibromide (HTMA-PFP) and poly{9,9′-bis[(6″- N -acetyltyrosine)hexyl]-2,7-fluorene- alt- 1,4-phenylene}, (Tyr–PFP) with neutral and charged surfactants has been studied. The optical spectroscopic properties of the three polymers in aqueous solution (PBS-PFP) and in DMSO–water mixtures (4% v/v, HTMA-PFP and Tyr–PFP) are also presented. Three different biocompatible surfactants were used: a single chain one, N α - lauroyl- l -arginine methyl ester hydrochloride (LAM), a gemini compound, N α ,N ω -bis( N α lauroylarginine) α, ω- dibutylamide dihydrochloride, (C 4 (LA) 2 ) and an amino acid glyceride conjugate, 1-O-( l -arginyl)-2,3-O-di-lauroyl-sn-glycerol dichlorhydrate (1212R). In addition, the interaction of the same polymers with three commonly used commercial non-ionic surfactants: n -dodecyl pentaoxyethylene glycol ether (C 12 E 5 ), 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton X-100) and polyethylene glycol sorbitan monolaurate (Tween 20) was also studied. Electronic spectroscopy (absorption and steady-state emission) as well as molecular dynamics using the Gromacs package (for the interaction between HTMA-PFP and Triton X-100) and ionic conductivity measurements on HTMA-PFP/C 12 E 5 are also reported.