Single crystals of crystalline block copolymers formed in n‐hexanol and methanol/DMF solutions: A comparative study

Abstract

Lamellar single crystals of poly(ɛ‐caprolactone) (PCL)‐based crystalline/liquid‐crystalline block copolymer (BCP) were prepared from two methods: solution crystallization in n‐hexanol as well as addition of methanol dropwise to BCP/DMF solution. The crystalline morphologies of PCL single crystals prepared at different temperatures were investigated. It was observed that well‐developed single crystals were formed in n‐hexanol at high crystallization temperatures, while low crystallization temperatures favored to fabricate well‐developed nanosheets in methanol/DMF. Annealing at the melting temperature of single crystals yielded the crystalline seeds and unimers in n‐hexanol, while it formed spherical micelles in methanol/DMF system. As a result, the size of single crystals in n‐hexanol could be tuned by addition of different ratios of unimer/seed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45089.

Interplay of Solvation and Size Effects Induced by the Counterions in Ionic Block Copolymers on the Basis of Hofmeister Series

“…The self‐assembly of amphiphilic block copolymers (BCPs) in selective solvents is increasingly attracting the attention of researchers in the past decades due to their potential applications in biological drug delivery, microreactor chemistry, and in novel nanostructural templating . In selective solvents, neutral BCPs can form various morphologies such as spheres, cylinders, vesicles, and lamellae, which can be regulated by many factors, such as block length, solvent composition, pH, and inorganic salt . Self‐assembly behaviors of these BCPs are well documented …”

Counterion‐Mediated Self‐Assembly of Ion‐Containing Block Copolymers on the Basis of the Hofmeister Series

“…[13][14][15] Specially, amphiphilic neutral block copolymers (BCPs) are of particular interest as they combine compositional diversity and high functionality with various assembly pathways to achieve well-controlled morphologies. [16][17][18][19][20][21][22][23][24][25] In the literature, this section of self-assembly behavior is now well-documented, which architecture leads to the formation of well-defined spherical aggregates in aqueous solution, whereas the randomness of charged units (qVBC) within the hydrophobic block of PS allows finetuning of the self-assembling properties by exchanging the counterions. We show that the hydrophilicity of the qVBC units is controlled by the nature of the different counterions, which is crucial in regulating the self-assembly process.…”

“…Self‐assembly process is of great importance in biological systems for the formation of well‐defined and monodisperse objects on multiple length scales, which is due to their potential applications in biological drug delivery, microreactor chemistry, and in novel nanostructural templating . Specially, amphiphilic neutral block copolymers (BCPs) are of particular interest as they combine compositional diversity and high functionality with various assembly pathways to achieve well‐controlled morphologies . In the literature, this section of self‐assembly behavior is now well‐documented, which results from an interplay of corona repulsive interactions, chain stretching in the core, and interfacial contributions …”

Recent progress in block copolymer crystallization

“…For BCPs, the noncrystallized block is covalently attached to the surface. Recent studies have focused on preparation techniques (thermal treatment versus co‐solvent), surface characteristics of the tethered chains, and functional crystalline nanoparticles . The review by Agbolaghi et al .…”