Small angle neutron scattering polystyrene

The conformation of polymer chains in an ultra-thin film has been an attractive subject in the field of polymer physics. The chain conformation has been extensively discussed theoretically and experimentally [6-11] however, the experimental technique to study an ultra-thin film is limited because it is difficult to obtain a signal from a specimen due to the low sample volume. The conformation of polymer chains in an ultra-thin film has been examined by small angle neutron scattering (SANS), and contradictory results have been reported. With decreasing film thickness, the radius of gyration, Rg, parallel to the film plane increases when the thickness is less than the unperturbed chain dimension in the bulk state [12-14]. On the other hand, Jones et al. reported that a polystyrene chain in an ultra-thin film takes a Gaussian conformation with a similar in-plane Rg to that in the bulk state [15, 16]. 

Fig. 53. Small-angle neutron scattering data from the 12-arm polystyrene star PS120A (Mw = 1.49 x 105) where the 11 deuterated arms were matched by the solvent THF. In order to demonstrate the asymptotic Q behavior, the data are plotted in a generalized Kratky representation (Iq01 vs. Q with a = 1.5 and 5/3). The solid line marks the high Q-plateau. (Reprinted with permission from [149]. Copyright 1989 American Chemical Society, Washington)...

Several experimental parameters have been used to describe the conformation of a polymer adsorbed at the solid-solution interface these include the thickness of the adsorbed layer (photon correlation spectroscopy(J ) (p.c.s.), small angle neutron scattering (2) (s.a.n.s.), ellipsometry (3) and force-distance measurements between adsorbed layers (A), and the surface bound fraction (e.s.r. (5), n.m.r. ( 6), calorimetry (7) and i.r. (8)). However, it is very difficult to describe the adsorbed layer with a single parameter and ideally the segment density profile of the adsorbed chain is required. Recently s.a.n.s. (9) has been used to obtain segment density profiles for polyethylene oxide (PEO) and partially hydrolysed polyvinyl alcohol adsorbed on polystyrene latex. For PEO, two types of system were examined one where the chains were terminally-anchored and the other where the polymer was physically adsorbed from solution. The profiles for these two... 

Briber RM, Bauer BJ (1991) Macromolecules 24 1899. By small-angle neutron scattering from blends of cross-linked and liner polystyrene they found that the intensity increased as the cross-link density was increased. This finding apparently contradicts our theoretical expression (4.11) below. See Sect. 4-4 for a comment on this point... 

The correlation length has been measured using scattering experiments, as discussed in Section 5.7. Small-angle neutron scattering (SANS) data on polystyrene in deuterated cyclohexane at 0 = 38.O°C are summarized in Fig. 5.8. These data are in good agreement with the power law expected by Eq. (5.52), shown as the line. 

Small-angle neutron scattering data for a semidilute solution of polystyrene (M = 1 100000 gmol ) in CS2 with i" = 0.025g/mr 2.5c. The curve is... 

Fig. 7.4. Small-angle neutron scattering. Cross-sections of deuterated polystyrenes (Afw = 5 x 105, p = 0.005 g/cm3) in solution in CS2. (From Farnoux.12)...

Yang et al. [27], using small-angle neutron scattering (SANS), reported the formation of supermolecular structures in polystyrene latex particles prepared by the seeded emulsion polymerization of styrene onto deuterated polystyrene particles. The recorded scattering intensities, which were much higher than those expected on the basis of the Debye random coil model, indicate the presence... 

Critical Phenomena of Deuterated Polystyrene and Hydrogenated Poly(vinyl methyl ether) by Small-Angle Neutron Scattering,... 

Kobayashi, M. Yoshioka, T Imai, M. Iton, Y. Structural ordering on physical gelation of syndiotactic polystyrene dispersed in chloroform studied by time-resolved measurements of small angle neutron scattering (SANS) and infrared spectroscopy. Mactvmolecules, 1995,28(22), 7376-7385. 

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