light scattering from polymer solutions and nanoparticle dispersions, 2007, p.200

[...]... (1.4) with N the number of scattering particles within the scattering volume V The scattering volume is defined by the intersection of incident light beam and optical aperture used for observing the scattered light intensity, and therefore depends on the scattering angle as shown in Fig 1.5 Fig 1.5 Dependence of the scattering volume on the scattering angle 1.2 Static Light Scattering 5 Fig 1.6 Angular... background of the two fundamental light scattering methods, that is static and dynamic light scattering, will be presented in more detail A few mathematical relations which are most essential for the practice of light scattering will be highlighted in grey boxes to stress their importance 1.2 Static Light Scattering As mentioned above, matter scatters electromagnetic waves (light) due to the induction of... scattered light is identical to that of the incident light Obviously, the maximum scattered intensity over the whole range of scattering angles is given for vertical polarization of the incident light, which is the reason why this scattering geometry is preferred in the experimental practice of light scattering 1.2.1 Scattering from Dilute Solutions of Very Small Particles For very dilute solutions. .. Concepts 1.2.2 Scattering from Dilute Solutions of Larger Particles For larger scattering particles, the scattered intensity is no longer independent of the scattering angle The so-called scattering vector q (in [cm−1]), which is experimentally determined by the scattering angle θ and the wavelength of the laser light λ provides a quantitative measure for the length scale of the static light scattering. .. solutions of small scattering particles (for example nanoparticles or polymer chains of size smaller than λ/20, see above), the scattering intensity is independent of the scattering angle and, in case scattering from the density 6 1 Fundamental Concepts fluctuations of the solvent itself is ignored, only depends on the scattering power of the dissolved particles b, their mass concentration c and the osmotic... value of q is derived from a given scattering geometry: Fig 1.7 Sketch of the definition of the scattering vector q = k − k 0 k 0 and k are the wave vectors of the incident and of the scattered light beam; θ is the scattering angle The scattering vector q is simply the difference of the two wave vectors, i e., q = k − k 0 For an elastic scattering process, k 0 = k = 2π λ , and therefore: q =q= 4π... of a random polymer coil (see also Table 1.2) As shown, one may consider light scattering also as an inverse microscopic technique, and the scattering vector as the resolution or magnification of the inverse microscope: the smaller q, the lower the magnification and the corresponding resolution of the structure of a given scattering particle (ii) The formalism presented here is valid for light scattering. .. resulting scattered intensity detected at a given scattering angle also change with time, reflecting the Brownian motion of the scattering particles, as illustrated in Fig 1.3 Fig 1.2 Interference pattern of light scattered from small particles (left) and from larger particles (right) For simplification, only two scattering centers are shown 1.2 Static Light Scattering 3 Fig 1.3 Sketch of the change in... charges To describe the interaction of light with matter, one has to consider that light has both particular and wave character Treating light within the classical wave picture, it is fairly simple to understand the origin of the phenomenon of light scattering: as an electromagnetic wave (a periodic modulation of electric and magnetic field strength both in space and time (see Eq 1.1) for the electric... detected The principle setup for any static light scattering experiment, defining the important quantities, is illustrated in Fig 1.4 I0 is the intensity of the incident light beam, Is the intensity of the scattered light, θ the scattering angle and rD the distance between sample and detector The polarizability α depends on the dielectric permittivity ε (and correspondingly on the index of refraction . class="bi x0 y0 w1 h1" alt="" Springer Laboratory Springer Laboratory Manuals in Polymer Science Schärtl, W.: Light Scattering from Polymer Solutions and Nanoparticle Dispersions ISBN: 3-540-71950-4. 3-540-65635-9 Pasch, Trathnigg: HPLC of Polymers ISBN: 3-540-61689-6 (hardcover) ISBN: 3-540-65551-4 (softcover) Wolfgang Schärtl Light Scattering from Polymer Solutions and Nanoparticle Dispersions. lack of a simple-to-read textbook for students and nonexperts interested in the basic principles and fundamental applications of light scattering. As part of the Springer laboratory handbook series,