An official website of the United States government
Abstract Polymer crystalsomes are a class of hollow crystalline polymer nanoparticles with shells formed by single crystals with broken translational symmetry. They have shown intriguing mechanical, thermal, and biomedical properties associated with spherical packing. Previously reported crystalsomes are formed by quasi‐2D lamellae which can readily tile on a spherical surface. In this work, the formation of polymer crystalsomes formed by 1D polymer crystals is reported. Poly (3‐hexylthiophene) (P3HT) is chosen as the model polymer because of its 1D growth habit. P3HT crystalsomes are successfully fabricated using a miniemulsion solution crystallization method, as confirmed by scanning electron microscopy and transmission electron microscopy. X‐ray diffraction (XRD) and selected area electron diffraction experiments confirm that P3HT crystallized into a Form I crystal structure. XRD, differential scanning calorimetry and UV–Vis results reveal curvature‐dependent structural, thermal and electro‐optical properties.
more »
« less
This content will become publicly available on February 3, 2026
Scrolled Poly( L ‐Lactic Acid) Single Crystals via Chain End‐Induced Symmetry‐Breaking
Abstract Single crystals that do not obey translational symmetry have been reported in various material systems. In polymers, twisted crystals are typically formed in banded spherulites, while a class of non‐flat polymer single crystals (PSCs) has been observed. Herein, we report the formation of scrolled single crystals of biodegradable polymer poly(L‐lactic acid) (PLLA). While classical 2‐dimensional single crystals formed in solution‐crystallized PLLA are flat, we show that PLLA crystals bend into scrolls when the polymer molecular weight is low. The formation of these unique scrolled PLLA single crystals depends on polymer chain ends and the polymer molecular weight. This work, therefore, demonstrates a new mechanism to break translational symmetry in PSC growth.
more »
« less
- Award ID(s):
- 2104968
- PAR ID:
- 10638637
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 64
- Issue:
- 6
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
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.more » « less
-
Abstract Block copolymer brushes are of great interest due to their rich phase behavior and value‐added properties compared to homopolymer brushes. Traditional synthesis involves grafting‐to and grafting‐from methods. In this work, a recently developed “polymer‐single‐crystal‐assisted‐grafting‐to” method is applied for the preparation of block copolymer brushes on flat glass surfaces. Triblock copolymer poly(ethylene oxide)‐b‐poly(l‐lactide)‐b‐poly(3‐(triethoxysilyl)propyl methacrylate) (PEO‐b‐PLLA‐b‐PTESPMA) is synthesized with PLLA as the brush morphology‐directing component and PTESPMA as the anchoring block. PEO‐b‐PLLA block copolymer brushes are obtained by chemical grafting of the triblock copolymer single crystals onto a glass surface. The tethering point and overall brush pattern are determined by the single crystal morphology. The grafting density is calculated to be ≈0.36 nm−2from the atomic force microscopy results and is consistent with the theoretic calculation based on the PLLA crystalline lattice. This work provides a new strategy to synthesize well‐defined block copolymer brushes.more » « less
-
Abstract Nanoparticle (NP) assembly has been extensively studied, and a library of NP superstructures has been synthesized. These intricate structures show unique collective optical, electronic, and magnetic properties. In this work, we report a bottom‐up approach for fabricating spherical gold nanoparticle (AuNP) assemblies that mimic colloidosomes. Co‐crystallization of lipoic acid‐end‐functionalized poly(ethylene oxide) (PEO) and AuNPs in solution via a self‐seeding method led to the formation of hollow spherical NP assemblies named nanoparticle crystalsomes (NPCs). Due to the spherical shape, the translational symmetry of PEO crystals is broken in NPCs, which can be attributed to the competition between NP close packing and polymer crystallization. This was confirmed by tuning the NPC morphology via varying the self‐seeding temperature, crystallization temperature, and PEO molecular weight. We envisage that this strategy paves the way to attaining exquisite morphological control of NP assemblies with broken translational symmetry.more » « less
-
In the earlier theoretical research, impact of entanglement on folding during crystallization was minimized. The combination of 13C isotope labeling and NMR spectroscopy allows us to quantitatively determine stem to stem distance as well as chain folding distance, hence, we are able to probe chain-level structure. Our recent work indicated that polymer chains are possible to fold prior to crystallization. In this poster, we would like to investigate the folding structure of a semi-crystalline polymer in melt-grown crystals (mgc) by using solid-state NMR spectroscopy and SAXS measurement. First, various 13C enriched poly(L-lactic acid) (PLLA) samples with different molecular weights (Mw = 2.5k – 300k g/mol) across critical entanglement length (Mc = 16k g/mol) were prepared in order to observe the molecular weight dependence of folding structure of PLLA. We revealed that entanglements influence the folding number during crystallization. Second, we attempt to observe the entanglement effect through diluting entanglement density, i.e., blending the PLLA above and below the Mc with different ratio and molecular weight. Based on the experimental results, we would like to highlight the impact of entanglements on folding of semicrystalline polymer in the melt-grown crystal.more » « less
