Surface characterization of silanized glass fibers by labeling with environmentally sensitive fluorophores

Abstract

SYNOPSISGlass fibers have been treated with y-aminopropyl-triethoxysilane (APES) through different silanizating procedures, which include APES aqueous solutions and APES vapor adsorption.Transmission Fourier transform I R (FTIR) measurements have been performed on the silanized samples to characterize the silanization reaction. Dansyl-sulfonamide conjugates have then been formed by reaction of dansyl chloride in dimethylformamide solution with the amine functionality's immobilized on the glass fiber surface. Steady-state and timeresolved fluorescence measurements have been performed on dansylated samples. A dependence of the fluorescence intensity and the wavelength of the maximum emission on the silanization procedure has been observed. Good fits of the fluorescence decays of dansyl labels are found when biexponential functions are used for deconvolution, whereas the decay of dansylamides in fluid solution is single exponential. A two-state model for the solid solvent relaxation seems t o apply for this samples. Several surface structural changes produced by the different silanization methods have been proposed. FTIR results support the conclusions drawn from fluorescence measurements. C3 1996 .John Wiley 6; Sons, Inc.

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“…To have some idea about the ane coating is not exactly known [1][2][3][4][5], although there adhesion mechanism between the silane coupling agents and the polymeric matrices, as proposed by Plueddeman [8], it is necessary to know how the polymer matrix One method used in the determination of local propthe figures, is presented in Table I. erties in polymer systems is the measurement of some portion of the optical response of a molecule that is sensiLabeling Procedure tive to a particular property of the local medium [9][10][11]. Pyrene and its derivatives are excellent probes or labels Well-dried silanized glass fibers were put in contact because they usually have long fluorescence lifetimes, for 10 min, at room temperature, with a PSC solution form emissive excimers or exciplexes, and have a fluores-(10 Ϫ4 M ) in acetonitrile (AcN).…”

Microstructural and wettability study of surface pretreated glass fibres

“…4 shows two regions of the FTIR spectra of activated samples. Although the detailed assignment of the IR bands can be found in [14], the main IR observations can be summarized as follows. As can be observed at about 3425 cm-1 the tension band of bounded water increases in a parallel way as the intensity of activation treatments: none < water < HCl(l h) < HC1(3 h).…”

“…ate surface (acid base properties and quantification of the number and dis tribution of surface silanol groups [1, [4][5][6]) and on the characterisation of the silane coupling agent coating-struc ture of the polyorganosiloxane layer [7][8][9][10][11][12][13][14] and orientation of the silane organo-functional groups. To the best of the authors' knowledge, no work has been undertaken on the effects of surface treatments, prior to the silanization, on the structure and properties of the silane coupling agent layer.…”

Effect of Glass Fiber Surface Treatments on Mechanical Strength of Epoxy Based Composite Materials

“…Recent studies have focused on the characterization of glass f ber coatings (18,21). Some f uorescent molecules, such as dansyl derivatives, show appreciable shifting in their f uorescence emission band depending on the polarity and/or rigidity of their surroundings (22,23).…”