Morphology of Ionic Aggregates in Carboxylato- and Sulfonato-Telechelic Polyisoprenes As Investigated by Small-Angle X-ray Scattering

Abstract

Twenty seven samples of carboxylato- and sulfonato-telechelic polyisoprenes associated with various cations (Na, K, Rb, Cs, Mg, Ca, Sr, and Ba) have been investigated by small-angle X-ray scattering. The Bragg spacing characteristic of the ionic peak is directly proportional to the root-mean-square end-to-end distance (r rms) of the polyisoprene chain. In the series of sulfonato-telechelic polyisoprenes, the Bragg spacing is approximately equal to r rms, whereas in the series of carboxylato-telechelic polyisoprenes it amounts to 21/2 r rms. It also appears that the ionic aggregates are more likely distributed according to a planar hexagonal network. An original method has been used for the tail-end analysis of the SAXS profile, which is based on the general vertex contribution to the Kirste−Porod law. It results that the ionic aggregates are of an angulous shape. Four different functions have been used to account for the interphase profile between the ionic phase and the polymeric matrix. The ionic aggregates would accordingly contain an average of 10 alkali-metal cations with a tetrahedral stacking, whereas six alkaline-earth-metal cations would be organized according to an equilateral prism. The oxygen atoms of the anionic groups mainly contribute to the width of the interface. The additional peaks observed in the upturn of the curve at very low angles are the signature of a superstructure similar to that one previously observed for carboxylato-telechelic poly(tert-butyl acrylate)s.

Morphological Analysis of Telechelic Ureidopyrimidone Functional Hydrogen Bonding Linear and Star‐Shaped Poly(ethylene‐co‐propylene)s

“…Stadler et al also observed a shifting of the SAXS maxima for urazoylbenzoic acid functionalized polybutadiene to a higher q for higher levels of functionality (lower molecular weight between functional groups) 23. Jérôme et al correlated Bragg spacing with molecular weight ( d ∼ $\overline M _{{\rm n},}$ 0.5 ) for telechelic polyisoprene ionomers, and similar trends with molecular weight were apparent for the present UPy functionalized polymers 25…”

Small-Angle X-ray Scattering and Small-Angle Neutron Scattering Studies of Liquid-Crystalline Halato(semi)telechelic Polymers

“…The greater the molecular weight, the smaller the s position and the intensity of this peak. This latter observation qualitatively agrees with previous results in the case of sulfonatopolyisoprenes neutralized with a metallic cation X (monovalent or divalent) where dw is proportional to the square root of the molecular weight (Mn) 1/2 (Sobry, Fontaine, Ledent, Foucart & Jrr6me, 1998). In other words, the characteristic distance between the aggregates increases with the polymer chain length.…”

Morphological Behavior of Sulfonated Styrene-Ethylene/Propylene-Styrene Triblock Copolymers

“…Sobry et al observed a similar trend of interdomain spacing with molecular weight for telechelically functionalized ionomers, finding that the interdomain spacing was proportional to the root-mean-square end to end distance (10).…”