Heterogeneities in random ionomers. A small-angle x-ray scattering investigation of alkylated polystyrene-based materials

Abstract

The effects of internal plasticization on the morphology of alkylated poly(styrene-co-cesium methacrylate) ionomers are studied using small-angle X-ray scattering. In agreement with previous mechanical studies of these ionomers, moderate levels of alkylation enhance ionic aggregation. However, very high levels of alkylation disrupt ionic aggregation. For intermediate levels of alkylation, the multiplet size remains fairly constant and is comparable to the multiplet size of the nonalkylated ionomer (radius of 3-4 A). The average distance between these multiplets is constant, regardless of the amount of side chain material attached to the polymer backbone between the ionic groups. As the degree of alkylation increases, the intensity of the small-angle upturn (SAUT) decreases. In light of the recent multiplet-cluster model for random ionomers, it is believed that internal plasticization allows more ion pairs to form multiplets, thus increasing the size of the clusters (i.e., the correlated regions). As these correlated domains become larger, the SAUT shifts to lower angles, resulting in an apparent progressive decrease in intensity in the observable range.

Synthesis and characterization of poly (styrene‐co‐vinyl phosphonate) ionomers

“…The single, broad scattering peak seen in Figure 10 for each of the samples, except for maybe the 2.4‐SVP ionomers, is similar to the “ionic peak” seen in most ionomers that is due to an ion‐rich microphase 41. In addition, the scattering intensity upturn at low q ( q = 4πsinθ/λ where λ is the X‐ray wavelength and θ is one‐half the scattering angle) is also characteristic of ionomers and is believed to arise from an inhomogeneous distribution of isolated ionic groups or multiplets 42, 43. A clear peak was not observed in the structure factor for the 2.4Na‐SVP, but a distinct shoulder can be seen in the SAXS curve for the 2.4Zn‐SVP.…”

Small-Angle X-ray scattering studies of Nafion®/[silicon oxide] and Nafion®/ORMOSIL nanocomposites

“…First, initialized membranes were immersed in stirred solutions of 3 : 1 (v/v) MeOH : H,O at 22°C for 20 h. Sorbed water initiates hydrolysis of TEOS, which was subsequently introduced in a quantity such that H,O : TEOS = 4 : 1 (mol/mol). Solutions of TEOS : MeOH = 3 : 1 (v/v) were added to the containers (subsequently stoppered), and stirring was maintained.…”

Sulfonated polystyrene ionomers containing 4-aminobenzoic acid studied by a small-angle X-ray scattering technique

“…8 Since partly crystalline ionomers have a wide range of application, extensive studies have been devoted to their morphology. [1][2][3]8 The morphology of polystyrene 7,[9][10][11][12][13][14][15][16][17][18][19][20][21][22] ionomers was also investigated widely using the SAXS technique.…”