Light scattering, calorimetry

So the hunt for this elusive entity, the growing nucleus, is open. Useful analytical techniques for the study of crystal nucleation and growth must be sensitive to the size of the evolving clusters, and, ideally, also to the detailed intermolecular structure of these clusters. The first requirement seems more within reach than the second. 

In an alternative to counting the number of condensed particles, one can try to monitor the concentration of remaining solute [44], or some other thermodynamic property that evolves with cluster formation for example, microcalorimetry can measure the heat absorbed as crystallization occurs, and thus can draw a de-supersaturation curve [45]. Needless to say, none of the above directly or indirectly touches upon the question of the internal structure of the generated clusters. 

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NMR IR/Raman EM ESR Fluorescence Neutron scattering X-ray Light scattering Calorimetry md ... 

PMAA was hydrophobically modified with stearyl or lauryl methacrylate and the interactions of these modified polymers with PC/cholesterol membranes were investigated by dynamic light scattering, calorimetry and fluorescence anisotropy. Vesicle diameter was observed to increase in the presence of polymer from -180 nm in the absence of polymer to -240nm at 10 wt.%. Vesicles containing 8 2 PC-Chol showed a relatively sharp transition at 51 °C that split into two peaks (51 C and - 46 ° C) at 10 wt.% polymer and then became one peak again at -44 C at 40 wt.% polymer. Meanwhile, 6 4 PC-Chol vesicles showed only a broad transition that sharpened at 40 wt.% polymer to a peak centered - 42 C. Lairryl-suhstituted copolymers showed more lipid-lipid disraption than stearyl substituted ones. 

NIN Ninni, L., Meirelles, A.J.A., and Maurer, G., Thermodynamic properties of aqueous solutions of maltodextrins from laser-light scattering, calorimetry and isopiestic investigations. Carbohydrate Polym., 59,289,2005. 

In a series of papers, Prokopova et al. [145-150] reported their studies on rheology, light scattering, calorimetry and infrared sj troscopy of morterately concentrated aqueous poly(vinyl alcohol) solutions. Their main conclusions are as follows. 

Figure 10.7 The phase diagram (a) and the glass transition temperatures (b) of a PSC/PVME mixture obtained, respectively, by light scattering and differential scanning calorimetry (DSC). Irradiation experiments were performed in the miscible region at 127 C indicated by (X) in the figure of trans-cinnamic acid-labeled polystyrene/poly(vinyl methyl ether) blends.

DSC Differential scanning calorimetry ELS(D) Evaporative light scattering (detector)... 

If a processing apparatus is constructed in such a way that the X-ray beam can irradiate the sample, it can most probably be mounted in the beamline. Suitable chambers allow for a change of sample temperature, humidity, strain, pressure, etc. Melts may be sheared during irradiation. Fibers can be spun in the beam. Several methods may be combined (SAXS, WAXS, calorimetry, light scattering) by utilization of sophisticated sample chambers. 

A3 AIBN c Cp DLS DLVO DSC EO GMA HS-DSC KPS LCST Osmotic third virial coefficient 2,2 -Azobis(isobutyronitrile) Polymer concentration Partial heat capacity Dynamic light scattering Derjaguin-Landau-Verwey-Overbeek Differential scanning calorimetry Ethylene oxide Glycidylmethacrylate High-sensitivity differential scanning calorimetry Potassium persulphate Lower critical solution temperature... 

Interpolymer complexes often display physical properties very different from their individual constituent molecules. As a result, these systems have been studied using a variety of techniques such as potentiometry, conductimetry, turbidity, viscometry, calorimetry, sedimentation, light scattering, spectroscopy, and electron microscopy [88]. 

Phase transitions Differential thermal analysis (DTA) or differential scanning calorimetry (DSC), light scattering and various spectroscopic techniques, diffraction methods (especially X-ray diffraction), measurement of thermal expansion and any other property changing with the transition... 

Several experiments were devoted to the study of polymers. One was devoted to the study of spin-coating (121). A second uses light scattering to measure polymer sizes (122). There were several approaches to polymer kinetics (39, 123, 124, 125). Finally there was one study using differential scanning calorimetry to study polymer glasses (126). All of these experiments on modem materials can be found listed in Table VIII. 

Critical phenomena of gels have been studied mainly by dynamic light scattering technique, which is one of the most well-established methods to study these phenomena [18-20]. Recently, the critical phenomena of gels were also studied by friction measurement [85, 86] and by calorimetry [55, 56]. In the case of these methods, the divergence of the specific heat or dissipation of the friction coefficient could be monitored as a function of an external intensive variable, such as temperature. These phenomena might be more plausible to some readers than the divergence of the scattered intensity since they can observe the critical phenomena in terms of a macroscopic physical parameter. 

Here we describe briefly the recent studies of the critical phenomena of gels by dynamic light scattering, friction coefficient measurement, and calorimetry. Some of the latest results by neutron scattering are also given. 

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