DOI: 10.1073/pnas.1801682115
论文题名: Close-packed block copolymer micelles induced by temperature quenching
作者: Chen L. ; Lee H.S. ; Lee S.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2018
卷: 115, 期: 28 起始页码: 7218
结束页码: 7223
语种: 英语
英文关键词: Block copolymer micelles
; Close-packed structures
; Nucleation
; Phase transition
Scopus关键词: block copolymer micelle
; copolymer
; unclassified drug
; aqueous solution
; Article
; chemical structure
; close packed structure
; controlled study
; cooling
; crystal
; heating
; micelle
; phase transition
; pressure
; priority journal
; temperature
; temperature quenching
英文摘要: Close-packed structures of uniformly sized spheres are ubiquitous across diverse material systems including elements, micelles, and colloidal assemblies. However, the controlled access to a specific symmetry of self-assembled close-packed spherical particles has not been well established. We investigated the ordering of spherical block copolymer micelles in aqueous solutions that was induced by rapid temperature changes referred to as quenching. As a function of quench depth, the quenched self-assembled block copolymer micelles formed three different close-packed structures: face-centered cubic (fcc), random stacking of hexagonal-close-packed layers (rhcp), and hexagonal-close-packed (hcp). The induced hcp and rhcp structures were stable for at least a few weeks when maintained at their quench temperatures, but heating or cooling these hcp and rhcp structures transformed both structures to fcc crystallites with coarsening of the crystal grains, which suggests that these noncubic close-packed structures are intermediate states. Time-resolved scattering experiments prove that the micellar rhcp structures do not originate from the rapid growth of competing close-packed structures. We speculate that the long-lived metastable hcp and rhcp structures originate from the small size of crystal grains, which introduces a nonnegligible Laplace pressure to the crystal domains. The reported transitions from the less stable hcp to the more stable rhcp and fcc are experimental observations of Ostwald’s rule manifesting the transition order of the key close-packed structures in the crystallization of close-packed uniform spheres. © 2018 National Academy of Sciences. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/163692
Appears in Collections: 气候变化与战略
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作者单位: Chen, L., Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, United States; Lee, H.S., Characterization Facility, University of Minnesota, Minneapolis, MN 55455, United States; Lee, S., Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, United States
Recommended Citation:
Chen L.,Lee H.S.,Lee S.. Close-packed block copolymer micelles induced by temperature quenching[J]. Proceedings of the National Academy of Sciences of the United States of America,2018-01-01,115(28)