TY - JOUR
T1 - Effect of Concentration on the Dissolution of One-Dimensional Polymer Crystals
T2 - A TEM and NMR Study
AU - Guerin, Gerald
AU - Molev, Gregory
AU - Pichugin, Dmitry
AU - Rupar, Paul A.
AU - Qi, Fei
AU - Cruz, Menandro
AU - Manners, Ian
AU - Winnik, Mitchell A.
PY - 2019/1/8
Y1 - 2019/1/8
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85059701466&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.8b02126
DO - 10.1021/acs.macromol.8b02126
M3 - Article (Academic Journal)
AN - SCOPUS:85059701466
SN - 0024-9297
VL - 52
SP - 208
EP - 216
JO - Macromolecules
JF - Macromolecules
IS - 1
ER -