Solution Crystallization Behavior of Crystalline−Crystalline Diblock Copolymers of Poly(ethylene oxide)-block-poly(ε-caprolactone)

Abstract

The crystallization behavior of crystalline-crystalline (CC) diblock copolymers has been shown to be dependent on the crystallization temperature and relative molecular size of each component. The behavior of copolymers with similar crystallization temperatures is controlled by the block with the larger weight fraction and solvent-polymer interactions. Using samples of poly(ethylene oxide)-block-poly-(ε-caprolactone) (PEO-b-PCL), dilute solution crystallization methods were investigated to determine their role in crystallization of CC copolymers. A single crystal of one block, either PEO or PCL (the first block), crystallized first with the second block segregated to the crystal basal surfaces. For the first time, solvent quality and homopolymer seeds were introduced to manipulate crystallization of the block with the smaller weight fraction to crystallize first and form the lamellar single crystal. In addition, subsequent crystallization of the tethered chains (the second block) on the surface was also observed, depending upon the molecular weight of the second block and crystallization conditions. These crystallites formed by the second block exhibited preferred orientations on the crystal surface as observed by electron diffraction. It is believed that this orientation was induced by "soft" epitaxy between the fold surfaces of the adjacent single crystals of the first block formed by the initial crystallization.

Synthesis of polymer nano-brushes by self-seeding method and study of various morphologies by AFM

“…Indeed, in mixed-brush growth systems, the quality of solvent for amorphous blocks in solution as well as the behavior of different chains grafted on the substrate surface lead to varying arrangements of polymer brushes. Amyl acetate at growth condition is very good and partially poor for PS and PMMA blocks in respect [18,19]. The interaction between PMMA brushes and PEG substrate is attractive.…”

“…The interaction between PMMA brushes and PEG substrate is attractive. However, the interaction between PS brushes and PEG substrate is repulsive [19,20]. These two kinds of interactions conduce to different Fig.…”

“Raft” Formation by Two‐Dimensional Self‐Assembly of Block Copolymer Rod Micelles in Aqueous Solution

“…Twinning occurs at angles of roughly 608 or 1208, which is consistent with the hexagonal shape known for PEO-b-PCL single crystals. [10] It is worth mentioning that similar twinning behavior also exists in inorganic nanoparticle systems. [11] Structures are not always symmetric about the axis associated with twinning, and some lamellae contain more than one of these axes.…”

Effect of miscibility on migration of third component in star‐like co‐continuous and disperse‐within‐disperse mixed brushes

“…The amorphous–amorphous–crystallizable ternary mixed brushes were developed using PEG 114 ‐ b ‐PS and PEG 114 ‐ b ‐PMMA diblock copolymers having amorphous coiled blocks and PEG 114 ‐ b ‐PCL or PEG 114 ‐ b ‐PLLA diblock copolymers with crystallizable coiled blocks. Amyl acetate as a growth solvent was very good for PS, good for PCL, poor for PMMA and very poor for PLLA, in processing conditions. The PEG substrate interactions were attractive with PLLA and PMMA,, , neutral with PCL and repulsive with PS brushes.…”