Effect of Concentration on the Dissolution of One-Dimensional Polymer Crystals: A TEM and NMR Study

Gerald Guerin*, Gregory Molev, Dmitry Pichugin, Paul A. Rupar, Fei Qi, Menandro Cruz, Ian Manners, Mitchell A. Winnik

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

6 Citations (Scopus)

Abstract

We report a study of the dissolution of core-crystalline polyferrocenyldimethylsilane-block-polyisoprene (PFS53-b-PI637, where the subscripts are the degrees of polymerization of the two blocks) micelle fragments in decane for different concentrations (ranging from 0.01 to 6 mg mL-1) by a combination of transmission electron microscopy (TEM) and high-temperature 1H NMR. We used self-seeding experiments at different temperatures as an efficient, although indirect, way to evaluate the dissolution of these micelles fragments. We annealed micelle fragment solutions at five different temperatures (50, 60, 65, 70, and 75 °C) for 30 min and cooled them to room temperature to regrow the micelles. The amount of micelle fragments that dissolved at the annealing temperature was then evaluated by comparing the length of the regrown micelles with that of the starting micelle fragments. We show that seed crystallites are less prone to dissolution as their concentration increases. In addition, by combining results of self-seeding experiments and 1H NMR measurements at 75 °C, we evaluated the percentage of unimer released upon the partial dissolution of seed fragments at 75 °C and established that the mechanism of seed fragment dissolution is also concentration dependent: at low concentrations, they dissolve in a cooperative process, whereas at high concentrations, they dissolve partially from both ends.

Original languageEnglish
Pages (from-to)208-216
Number of pages9
JournalMacromolecules
Volume52
Issue number1
Early online date19 Dec 2018
DOIs
Publication statusPublished - 8 Jan 2019

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