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Steady state fluorescence (SSF) technique was used for studying dissolution of UV-induced polymer films. These films are formed from poly(methyl methacrylate) (PMMA) chains labeled with pyrene (P) which was introduced as a fluorescence probe to monitor the dissolution processes. PMMA films in various ethylene glycol dimethacrylate (EGDM) content, cured by UV radiation, were dissolved in chlorofrom-heptane...
New organo-soluble and blue-emissive fluorene-based polyoxadiazoles, PFO x and PFO x EH, exhibit colorimetric and fluorescent acid-sensory properties to a strong acid due to the weak basicity of imine-type nitrogen atom(s) in an 1,3,4-oxadiazole ring. To further investigate their protonation with an acid, 1 H NMR spectroscopy and AM1 semiempirical quantum-mechanics are utilized...
Both pyrene-fluorescence probe and fluorescence label techniques are used to investigate the association behaviors of hyperbranched poly(sulfone-amine) (HPSA) in aqueous solution. In the presence of HPSA, excimer emission peak evidently appeared, while no excimer peak was observed in the emission spectra in the absence of HPSA. The excitation spectrum monitored at excimer emission red shifts by about...
Water uptake phenomena was studied in a group of commercial epoxy based thermosets using gravimetric and fluorimetric analysis. The different epoxy formulations were labeled with two dansyl derivatives differing in the spacer length between the chain and the fluorophore moiety. The fluorimetric method consisted of monitoring the changes in the first moment of the dansyl emission band as a function...
A real-time monitoring of excimer emission fluorescence probe di(1-pyrenemethyl)ether (DiPyM) was used for study swelling interpenetrating polymer network (IPN) consisting of polyethylene/poly(styrene-co-butylmethacrylate) (PE/P(S-co-BMA)) and containing different network density. DiPyM was introduced into IPN during polymerisation or was penetrated into blocks from toluene solution. The effect of...
Fluorescence sensor techniques have been developed for monitoring nonisothermal polymerization reactions as well as for mixing of resin components both at the nanoscale and macroscale. A polarity-sensitive probe, 4-(N,N-dimethylamino)-4'-nitrostilbene (DANS), was used to monitor the cure of an industrially relevant epoxy resin system through a fluorescence emission intensity ratio, which is self-referencing...
Novel fluorescent derivatives of generation 0 polyamidoamine (PAMAM), comprising 1,8-naphthalimide units have been synthesized. Their basic photophysical properties in organic solvents of different polarity have been determined and discussed. A 4-N,N-dimethylaminoethylene-1,8-naphthalimide, labelled PAMAM, has been synthesized with designed fluorescent intensity and high sensitiveness to the presence...
In situ steady state fluorescence (SSF) technique was used to study the dissolution of disc-shaped polymer glasses in various molecular weights, M W . The glass discs were formed by free-radical polymerization of methyl methacrylate (MMA). Pyrene (P) was introduced during polymerization as a fluorescence probe to monitor the dissolution process in chloroform. Desorption of poly(methyl methacrylate)...
This study describes the effect of salt on the aqueous solution property of the anionic terpolymer (SPM/NIPAM/PyMMA) of potassium-2-sulfopropylmethacrylate (SPM), N-isopropylacrylamide (NIPAM), and 1-pyrenemethylmethacrylate (PyMMA) in terms of fluorescence and dynamic light scattering. A plot of the thermally induced changes in I 1 /I 3 and I E /I M ratios for pyrene-labeled...
The gelation during free-radical crosslinking copolymerization (FCC) of styrene (S) and commercial divinylbenzene (DVB) in bulk was studied using Fast Transient Fluorescence (FTRF) technique. Pyrene (Py) was used as a fluorescence probe for the FTRF experiments. Fluorescence lifetimes of Py from its decay traces were measured and used to monitor the gelation processes in various DVB contents. Styrene...
Binding of cationic surfactant cetyltrimethylammonium bromide (CTAB) on polyelectrolytes ADDan containing different amounts of sulfonate groups was studied by fluorescence spectrum of dansyl labels in aqueous solution. With increasing concentration of CTAB, there was an abrupt drop in the emission maximum wavelength λem and a sharp increase in the relative intensity RF defined as the ratio of emission...
Poly(N-isopropylacrylamide), PNIPAM, undergoes phase separation, upon heating under semi-dilute conditions, at 32 o C, the lower critical solution temperature (LCST). Upon subsequent cooling, the dispersion rapidly clears again, at the LCST, to form a single, homogeneous phase. In this paper we report that fluorescence techniques, including quenching and time-resolved anisotropy measurements...
Fluorescent spectra of dansyl-labeled copolymers containing 2-acrylamido-2-methylpropanesulphonic acid (AMPS) and N,N-dimethylacrylamide (DMAA) with 0.2mol% chromophore were observed in aqueous solution. Two emission bands appeared at 336 and 533nm for protonated and unprotonated species of the label, respectively. These wavelengths were independent of the mole fraction F AMPS ...
The time-resolved fluorescence anisotropy behaviour of pyrene solubilized (10 -6 M) in ultra-dilute (10 -3 wt%) aqueous solutions of the thermoresponsive polymer poly(N-isopropylacrylamide), PNIPAM, shows unusual characteristics. Rather than decay to zero (as expected of a freely rotating species in a homogeneous fluid environment) the anisotropy of the emission from the...
A dansyl labeled polyelectrolyte (ADDan60) was prepared by copolymerization of ionizable monomer 2-(acrylamido)-2-methylpropanesulphonic acid (AMPS) with N,N-dimethylacrylamide (DMAA) and N-[2–[[[5–(N,N-dimethylamino)-1-naphthalenyl]-sulfonyl]amino]ethyl]-2-propenamide (DANSAEP, 0.2mol%). Reduced viscosity ηsp/c, electrolytic conductivity κ, and fluorescent spectrum of ADDan60 in DMSO/THF mixtures...
Fast transient fluorescence technique (FTRT) was used to measure pyrene (Py) lifetimes during dissolution of glassy polymer, which is formed by free radical polymerization of methyl methacrylate (MMA), and Py was introduced during polymerization as a fluorescence probe to monitor swelling and dissolution. The dissolution process of poly(methyl methacrylate) (PMMA) glass was performed in chloroform...
The crystallinity of poly(ethylene terephthalate) (PET) films was investigated by comparing measurements of fluorescence, differential scanning calorimetry and density. It was found that the ratio of the fluorescence intensity at 330nm to that at 370nm can be an effective indicator of crystallinity. The dynamic process of recrystallization was directly observed for PET prepared using a spin-casting...
Intermolecular complex formation between mesogenic terphenyldiimide moieties of a thermotropic liquid-crystalline (LC) polyimide (P-11TPE) was studied by steady-state fluorescence and fluorescence lifetime measurements together with differential scanning calorimetry (d.s.c.) and wide-angle X-ray diffraction (WAXD). The P-11TPE shows various highly-ordered crystalline phases and a smectic phase during...
By using fluorescence spectroscopy together with d.s.c. and WAXD, structure analysis for main-chain thermotropic LC polyesters (PB-n), containing n=7-18 methylene units, was carried out. The strong excitation-wavelength dependence of fluorescence and red shift of fluorescence peak wavelengths excited at various wavelengths during heating for all PB-n were found to depend on different degrees of overlap...
Thiophene- and benzene-modified nickel poly-yne polymers 1-5 were characterized by gel permeation chromatography, infrared spectroscopy and X-ray photoelectron spectroscopy. The polymers, being highly soluble in common organic solvents, exhibit intense fluorescence upon excitation by ultraviolet-visible light at room temperature. The emission intensity of the polymers with thiophene-2,5-diyl is 8-277...
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