Fibres surface analytical techniques

As ToF-SIMS is a surface analytical technique, it is well suited to the study of surface interaction between a material and its environment or between a material and products applied to it. The surface modifications can then be studied, making it possible to establish links with degradation processes. Published papers on the study of natural fibres related to cultural heritage typically illustrate this aspect of ToF-SIMS analysis. 

The interface between plastic and wood fibres strongly influences the mechanical properties of a plastic/wood fibre composite. A means for evaluating the effectiveness of surface treatment on the wood fibres in the PVC/wood fibre composites is presented that investigated the adhesion between PVC and laminated wood veneers. Wood veneers were first treated with gamma-aminopropyltriethoxysilane, dichlorodiethylsilane, phthalic anhydride, and maleated PP for surface modification. The chemical modification made on the wood surfaces was then characterised by different complementary surface analytical techniques X-ray photoelectron spectroscopy and surface tension measurements. 63 refs. 

Infrared spectroscopy is certainly one of the most important analytical techniques available to today s scientists. One of the great advantages of infrared spectroscopy is that virtually any sample in virtually any state may be studied. Liquids, solutions, pastes, powders, films, fibres, gases and surfaces can all be examined with a judicious choice of sampling technique. As a consequence of the improved instrumentation, a variety of new sensitive techniques have now been developed in order to examine formerly intractable samples. 

Table 5.36 shows the main features of NSOM. Optical fibre tips for NSOM with high light transmission permit surface analytical and spectroscopic applications (fiuorescence imaging, Raman) with high spatial resolution (ca. 30 nm) and high chemical information content [337], NSOM overcomes critical measurement limitations of both far-fleld vibrational microscopes (low spatial resolution) and scanned probe microscopes (lack of chemical specificity). NSOM offers conventional optical characterisation and contrast mechanisms with the resolution of SPM. The spatial resolution of this relatively new technique is almost competitive with that of SEM. Consequently, NSOM is expected to become a serious alternative for SEM, since it is non-destructive if visible light is used, and allows visualisation of specimens in air. The technique holds considerable promise for the future. At the present time it is still quite expensive. 

The solvent-free micro extraction technique SPME is an important step towards the instrumentation and automation of the SPE technique for online sample preparation and introduction to GC-MS (Zhang et al., 1994 Eisert and Pawliszyn, 1997 Lord and Pawliszyn, 1998). It involves exposing a fused silica fibre coated with a liquid polymeric material to a sample containing the analyte. As an extraction and enrichment technique it compares to P T methods (MacGillivray et al., 1994). Also derviatization steps can be coupled to the extraction process for polar compounds and improved efficiencies (Pan et al., 1997). The typical dimensions of the active fibre surface are 1 cm X100 pm. 

Organic polymers and optical fibres [17] have been previously used to detect vapours of explosive analytes [18,19]. The transduction methods include absorption, fluorescence, conductivity, etc [16]. Such simple techniques are promising, because they can be incorporated into inexpensive and portable microelectronic devices. For example, a chemically selective silicone polymer layer on a SAW (surface acoustic wave) device has been shown to provide efficient detection for the nitroaromatic compounds [20]. The fluorescence of pentiptycene conjugated polymers [21,22] and... 

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