Confined and Directed Polymer Crystallization at Curved Liquid/Liquid Interface

Abstract

Spherical crystals are ubiquitous in nature and the necessary breaks in translational symmetry not seen in flat crystals render them structurally unique. Polymer crystals have been shown to exhibit nonflat morphologies, but control over their formation is difficult to achieve. One strategy is directing the crystallization by spatially and/or temporally tuning chain segmental mobility. This has been studied early on using polymer blends or polymer/solvent systems where coupling liquid–liquid phase separation with crystallization could provide morphological control. In this Trend article, a recent trend in using miniemulsion systems to act as nanoscale confinement on chain segmental mobility is reviewed. The confinement at this length scale causes unique features to arise in ordering processes such as liquid–liquid phase separation and crystallization that are not observed at the macroscale. The generality of this approach makes it a good candidate to direct the formation of new and unique hierarchical polymer nanostructures that could be utilized in numerous applications.

Crystallization kinetics of high‐density and low‐density polyethylene on carbon nanotubes

“…It is evident that the polymer crystals have grown extensively along the long axis of CNTs so that individual CNTs are difficult to detect. This periodic arrangement of polymer discs along the CNTs is referred as NHSK architecture . However, as CNT loading is high (20 wt%) in our case, a robust and trans‐crystalline layer was also observed, which is in agreement with previous findings …”

“…This periodic arrangement of polymer discs along the CNTs is referred as NHSK architecture. [27,35] However, as CNT loading is high (20 wt%) in our case, a FIGURE 2 Scanning electron micrographs of (A) LDPE-CNTs, and (B) HDPE-CNTs NHSK. Abbreviations: CNTs, carbon nanotubes; HDPE, highdensity polyethylene; LDPE, low-density polyethylene; NHSK, nanohybrid shish-kebab robust and trans-crystalline layer was also observed, which is in agreement with previous findings.…”

Polymer crystallization at liquid‐liquid interface

“…Several directions have been taken to confine the crystallization including BCPs, anodic aluminum oxide membrane, thin films, and water surface . We recently investigated using an L/L interface to confine the crystallization process . Specifically, we utilize a miniemulsion system where a polymer/poor solvent serves as the dispersed phase with droplet size of tens to hundreds of nanometers in an aqueous medium.…”

“…[60] We recently investigated using an L/L interface to confine the crystallization process. [127][128][129][130] Specifically, we utilize a miniemulsion system where a polymer/poor solvent serves as the dispersed phase with droplet size of tens to hundreds of nanometers in an aqueous medium. A phase diagram of the polymer/poor solvent is then utilized to control the ordering processes of the dispersed phase within the droplet.…”

Confined Crystal Melting in Edgeless Poly(l-lactic acid) Crystalsomes

“…An interesting question therefore arises: how does an edgeless lamellar crystal melt? To create an edgeless lamellar crystal, we consider the recently discovered spherical crystalsomes, which are single crystal-like hollow crystalline shells. − Due to its spherical shape, no exposed crystalline lateral surfaces exist in a closed crystalsome. Two types of approaches have been used to grow this unique structure.…”