pH-controlled assembly and properties of LbL membranes from branched conjugated poly(alkoxythiophene sulfonate) and various polycations.
We report on multilayer layer-by-layer (LbL) films of the conjugated polymer sodium poly[2-(3-thienyl)ethyloxy-4-butylsulfonate] (PTH) assembled with polycations: poly(diallyldimethylammonium chloride) (PDDA), 20% quaternized poly(N-ethyl-4-vinylpyridinium bromide) (Q20), poly(ethylene imine) (PEI), and poly(allylamine hydrochloride) (PAH). These films were prepared through spin-assisted LbL assembly under various pH conditions. We demonstrated a crucial role of the deposition pH in formation of PTH/polycation films and showed that decrease in the deposition pH from 7.5 to 2.5 limits the PTH multilayer formation to Q20/PTH and PDDA/PTH films due to reduced charge density in the poly(thiophene) chains. We show that optical and surface properties of the resulting PTH/polycation films can be tuned by varying a polycation component and/or by varying the deposition pH. The fluorescence properties of the Q20/PTH, PEI/PTH, and PDDA/PTH films are pH-dependent, and the films exhibit the drastic changes in photoluminescent intensity when transferred into solutions with different pH values, which may find useful in optical sensing applications.
Kozlovskaya
Veronika
V
School of Materials Science and Engineering , Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Kharlampieva
Eugenia
E
Jones
Keith
K
Lin
Zhiqun
Z
Tsukruk
Vladimir V
VV
D002412:Cations / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007097:Imines / Q000737:chemistry*; D008567:Membranes, Artificial; D015394:Molecular Structure; D010316:Particle Size; D011073:Polyamines / Q000737:chemistry*; D011095:Polyethylenes / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013499:Surface Properties; D013876:Thiophenes / Q000737:chemistry*
D002412:Cations; D007097:Imines; D008567:Membranes, Artificial; D011073:Polyamines; D011095:Polyethylenes; D011145:Polyvinyls; D000644:Quaternary Ammonium Compounds; D013876:Thiophenes; C551285:poly(2-(3-thienyl)ethyloxy-4-butylsulfonate); C505405:poly(ethylene imine); C027968:poly-4-vinyl-N-ethylpyridine; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; C063994:polyallylamine