Inside the Ionic Aggregates Constrained by Covalently Attached Polymer Chain Segments: Order or Disorder?

Abstract

When a small-molecule ionic crystal is group-substituted with polymer chain-segments to form an ionomer, do its constrained ionic aggregates maintain ordered internal structures? This work presents, for a Na-salt sulfonated-polystyrene ionomer, reconciled TEM electron-diffraction schlieren textures and WAXS Bragg-type reflections from the ionic-aggregate nanodomains, which solidly prove the aggregates’ internal (mono)­crystalline order. The observed DSC endotherm of the ionomer, identified by WAXS as an order–disorder transition interior to its aggregates, gradually becomes enhanced over a 3-month, room-temperature physical aging process, indicating that the aggregates’ ordering is a slow relaxation process in which the degree of order increases with time. This work corroborates an uncommon form of order, i.e., polymer-bound small-molecule ionic (quasi)­crystal, which is supplementary to the order phenomena in small molecules, polymers, and liquid crystals.

Microstructural Capture of Living Ultrathin Polymer Brush Evolution via Kinetic Simulation Studies

“…In the last decade, the interest in experimental studies of end-functionalized linear polymer systems has increased considerably, − especially inasmuch as they provide well-characterized examples of much larger class materials of “self-assembled polymers”. The terminology of self-assembling applies to any flexible and cylindrical polymeric superstructure or polymer-like materials, which are obtained by the aggregation of one or more type of molecules in solution or in melt or reversible linear polymerization.…”