Structure of ionic aggregates of ionomers. II. Effect of humidity and temperature on ethylene and styrene ionomers

Abstract

Small‐angle X‐ray scattering profiles of ethylene and styrene ionomers were studied to clarify the structure of ionic aggregates as a function of humidity or temperature. The intensity and position of ionic cluster peaks were observed for ionomers with a certain degree of neutralization. The intensity of the ionic cluster peak for the ethylene ionomer increased with increasing relative humidity, but it decreased for the styrene ionomer. With increasing humidity, the position of the ionic cluster peak shifted to smaller angles for both ionomers. The size of the ionic aggregates and the closest approach distance between the aggregates were analyzed, and the results varied with humidity for both ionomers. The size did not vary markedly with a change in temperature, whereas the closest approach distance and number of ionic aggregates changed slightly with the melting temperature of the ethylene ionomer and the glass‐transition temperature of the styrene ionomer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 831–839, 2002

Dynamics of Sulfonated Polystyrene Ionomers Using Broadband Dielectric Spectroscopy

“…During the past 30 years there have been a number of studies of ionomer morphology by techniques such as small-angle X-ray scattering (SAXS), − transmission electron microscopy (TEM), − and dynamic mechanical analysis (DMA). ,− However, there have been few systematic investigations of the dynamic relaxation behavior of amorphous ionomers using dielectric relaxation spectroscopy (DRS) and none on sulfonated polystyrene (SPS) ionomers that we are aware of. DRS is powerful tool for understanding the influence of ions on segmental and local motions as well as aggregate dynamics.…”

“…Enhancements in mechanical properties result primarily from the aggregation of ionic species into clusters, which serve as physical cross-links. 3 During the past 30 years there have been a number of studies of ionomer morphology by techniques such as small-angle X-ray scattering (SAXS), [4][5][6][7][8][9][10][11][12][13][14] transmission electron microscopy (TEM), [14][15][16][17][18] and dynamic mechanical analysis (DMA). 6,[19][20][21][22] However, there have been few systematic investigations of the dynamic relaxation behavior of amorphous ionomers using dielectric relaxation spectroscopy (DRS) and none on sulfonated polystyrene (SPS) ionomers that we are aware of.…”

Review and critical analysis of the morphology of random ionomers across many length scales

“…Form-factor scattering is scattering due to the shape of a scattering object, structure-factor scattering is due to the arrangement of scattering objects in space. The form [84] SPU (Na, Ca, Ni, Cd Zn, Cs, Eu) Effect of polyol type and molecular weight [127] Polyisoprene telechelic carboxylate (Ca, Sr, Ni, Zn, Cd) Effect of cation type [126] SPU (Na) Effect of polyol type and molecular weight, various extension of Yarusso-Cooper model tested [128] SPU (Na) Using deformation to evaluate models [81] EMAA (Na, Zn, Cu, Fe), SMAA (Na) Effect of ion content, neutralization level, and ion type [129] EMAA (Na), SMAA (Na) Effect of temperature and humidity [79] MAH ionomers (Zn, Cs, Li, K, Na, Ba, Mg) Cation type [80] MAH ionomers (Zn) Neutralization level [57,130] SMAA (Cu) Compare Yarusso-Cooper and STEM [124] SMAA (Cu), 3-methylstyrene-MAA (Cu) Sample preparation method [131] Sulfonated poly(vinylidene fluoride) (Na) Check to see if Yarusso-Cooper model fit pattern factor of monodisperse small spheres can change the location of the peak maximum substantially; however, a reasonable polydisperse size distribution does not. Hence, it is probably perfectly acceptable to calculate an average spacing between scattering objects from the position of the SAXS peak.…”

Design of Cluster-free Polymer Electrolyte Membranes and Implications on Proton Conductivity

“…The typical value of the average distance between clusters, d cluster , is 5 nm. In Table we show literature data for a wide variety of charged polymers: polymers with both strong and weak acidic groups (e.g., sulfonic vs carboxylic acid groups), polymers neutralized with metallic counterions such as sodium and zinc, dry and hydrated polymers, crystalline and amorphous polymers, random copolymers and block copolymers. − Also included in Table is recent work on the synthesis and characterization of precise ionomers wherein the ionic groups are located periodically along the backbone. ,,, It is remarkable that the values of d cluster obtained from all of the systems listed in Table lie between 1.8 and 6.0 nm.…”