Light scattering wide-angle

The concentration of the polymer molecules eluting from SEC columns is continuously monitored by a detector. The most widely used detector in SEC is the differential reftactometer (DRI), which measures the difference in refractive index between solvent and solute. Other detectors commonly used for SEC are functional group detectors ultraviolet (UV) and infrared (IR), and absolute molecular weight detectors low angle laser light scattering (LALLS) and in-line continuous viscometers. Applications of these detectors to SEC analysis will be discussed later in the Multiple Detectors Section. Other detectors also being used are the densimeter (11-19) and the mass detector (20-23). 

There are a number of estimates of the actinic flux at various wavelengths and solar zenith angles in the literature (e.g., see references in Madronich, 1987, 1993). Clearly, these all involve certain assumptions about the amounts and distribution of 03 and the concentration and nature (e.g., size distribution and composition) of particles which determine their light scattering and absorption properties. Historically, one of the most widely used data sets for actinic fluxes at the earth s surface is that of Peterson (1976), who recalculated these solar fluxes from 290 to 700 nm using a radiative transfer model developed by Dave (1972). Demerjian et al. (1980) then applied them to the photolysis of some important atmospheric species. In this model, molecular scattering, absorption due to 03, H20, 02, and C02, and scattering and absorption by particles are taken into account. 

Kulicke W-M, Kniewske R (1980) Purification of aqueous and non-aqueous polymer solutions for light scattering measurements and a comparison of molecular weights determined with a low-angle and a wide-angle-photometer Makromol Chem, Rapid Commun 1 719... 

FSC]), strongly related to cell size) against light scattered at a wide angle (side scatter [SSC], which is influenced by cell structure and granularity). 

Laser light scattered by the particles is collected by the tip of a glass rod, ensuring an efficient light collection, in a rather wide spatial angle. The direct laser light is absorbed in a... 

The dependence of the light scattering patterns on a wide variety of variables may be explored, i.e. size, angle, intensity or combination of intensities such as the depolarization ratio i2/ii or the polarization (i2-ii)/(i2+ii) ... 

The applications of wide angle light scattering are beyond the scope of this work and too numerous to be summarized here but we would like to call attention to some comprehensive reviews (12, 13), basic treatises ( 5, 6), conference proceedings (14, 13) and finally some representative articles, selected from our own experience, that introduce the basic size distribution information obtainable from wide angle light scattering. 

The simplest demonstration of wide angle light scattering may be found in the measurements of the light scattered by single aerosol droplets of dioctylphthalate (16, 17). 

Recently, a four-laboratory cooperative study has led to a comparison of the determination of particle size distribution by electron microscopy, quasi-elastic light scattering and wide angle light scattering (20). 

The methodical relationship of angular light scattering to turbidity and dynamic light scattering is given. The wide angle... 

Wide angle light scattering is used as the principal probe to examine the core-shell structure proposed for certain acrylic acid acrylate ester copolymer latexes. Additional techniques were sedimentation and photon correlation spectroscopy. 

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