Epitaxial orientation and localized microphase separation prior to formation of nanohybrid shish-kebabs induced by one-dimensional nanofiller in miscible diblock copolymers with selective interaction

Competition Between Interfacial Interaction and Microphase Separation in Crystallization of Filled Block Copolymers

“…Therefore, the one‐dimensional nanofiller tends to absorb the crystallizable segments rather than the noncrystallizable segments, eventually promoting microphase separation. These two factors have been investigated in our previous research on crystalline‐amorphous diblock copolymers without repulsive interaction . Third, the repulsive interaction exists between the two blocks, which is the main reason for the difference in the demixing parameters of these different copolymers in Figure .…”

“…For instance, it has been reported that a small amount of nanofiller in the olefin diblock copolymer solution is sufficient to induce heterogeneous crystallization of the block copolymer, ultimately forming a typical NHSK structure . In our previous research, we have investigated the formation mechanism of the NHSK structure in different polymer systems containing nanofiller, such as homopolymers, random copolymers, and crystalline‐amorphous diblock copolymers . The results imply that chain segments can be absorbed on the surface of the nanofiller and simultaneously orient along its long axis under the synergic effect of polymer–filler interaction and filler geometry, leading to the formation of the NHSK structure .…”

“…In the NHEB structure, MWCNTs are surrounded by disk‐shaped folded‐chain lamellae of PE chains, while PVCH chains wrap around the lamellar crystals. Previously, based on dynamic MC simulations, the formation details of the NHEB structure formed in crystalline‐amorphous diblock copolymers containing one‐dimensional nanofiller without considering the interaction between blocks have been revealed by our group . However, the repulsive interaction strength between different blocks, which is difficult to control effectively in experiments, will also influence crystallization process of filled block copolymers, deserving more in‐depth investigations.…”

“…Besides, it can be known that the larger value of B 1 / E c corresponds to the actual system with stronger attractive interaction strength between the crystallizable monomers and the nanofiller, the larger value of B 2 / E c corresponds to the actual system with stronger repulsive interaction strength between crystallizable monomers and noncrystallizable monomers, and the larger value of E f / E c indicates that the sliding diffusion of polymer chains in crystals is more difficult. In the current system, B 1 / E c was chosen as −1 to allow the presence of appropriate attractive interactions between the crystallizable blocks and the nanofiller (previous studies have shown that too high or too low interfacial interactions both can lead to inhibition of the nanofiller's contribution to crystallization; in the system with too low interfacial interactions the filler cannot act as an effective nucleating agent for polymer crystallization, while in that with too high interfacial interactions the mobility of chains in interfacial regions is strongly restricted by the filler), E f / E c was fixed at 0.02 to allow chains to slide in crystals with a relatively strong mobility, and kT/E c ( k represented the Boltzmann's constant and T denoted the simulation temperature) corresponded to the reduced system temperature. In addition, previous studies suggested that B 2 / E c = 0.5 is sufficient for the occurrence of microphase separation .…”

“…In general, nanofillers act as nucleating agents to promote crystallization and induce the formation of crystal structures with various morphologies, which remarkably depend on filler size, filler content, and polymer–filler interaction . In particular, the incorporation of nanofillers also affects crystallization behaviors of block copolymers . Ochoa observed that the addition of cellulose nanofibers (CNFs) can increase the final crystallinity of polyethylene‐b‐polyethylene glycol (PE‐b‐PEG) diblock copolymers .…”