Thermal Transformations in Extruded Saloplastic Polyelectrolyte Complexes

Abstract

Extruded, salt-plasticized complexes of hydrated p o l y ( s t y r e n e s u l f o n a t e ) , P S S , a n d p o l y -(diallyldimethylammonium), PDADMA, were analyzed by differential scanning calorimetry and dynamic mechanical thermal analysis. Whereas the enthalpic signatures were weak, the latter technique revealed a strong transition in modulus, identified as a glass transition. The temperature of this transition, T g , varied with deformation rate as expected from time/temperature superposition. T g also decreased with increasing salt doping, which breaks ion pairing in the complexes, confirming the plasticizing effect of doping. Time, temperature, and salt concentration data were superposed to demonstrate the trends/equivalence of these three variables, and an empirical equation was used to connect them. Measurement time regimes were discussed with reference to the average lifetime of an ion pair.

Spontaneous Assembly of Miktoarm Stars into Vesicular Interpolyelectrolyte Complexes

“…This again indicates that the IPEC wall is rather static. Increasing the salt concentration is not a natural choice: increasing the dynamics within the IPEC membrane and softening it by salt decreases the driving force for IPEC formation (the used 0.3 M NaCl is a good compromise between the plasticizing effect and the screening effect of salt) 39. We can only speculate on the reasons for the presence of kinks.…”

Quasi-Spherical Cell Clusters Induced by a Polyelectrolyte Multilayer

“…The thickness of PEMUs depends on the salt concentrations from which they are grown: the thickness of PDADMA/PSS is roughly proportional 31 to [NaCl] up to 1.5 M NaCl, where the system enters a glass transition at room temperature. 32 The modulus sensed by cells depends on the modulus of the film and the proximity of the substrate: the effective modulus sensed by cells on multilayers increases for thinner multilayers. 15,33 3T3 fibroblast behavior on multilayers was recorded, using live cell imaging (which avoids artifacts from fixing), after 3 days of culture on the surfaces ( Langmuir XXXX, XXX, XXX−XXX C that of cells on the tissue culture plastic (TCP) control surface, Figure 1E.…”

Saloplastics: Processing Compact Polyelectrolyte Complexes

“…As with other measurements, the PEC remains in contact with aqueous solution of defined ionic strength to maintain an equilibrium content of water and counterions (doping level). Rheometry experiments of dense stacks of exPEC tapes have revealed some interesting mechanical properties …”