Title: Geometry induced sequence of nanoscale Frank–Kasper and quasicrystal mesophases in giant surfactants

Abstract

Frank–Kasper (F-K) and quasicrystal phases were originally identified in metal alloys and only sporadically reported in soft materials. These unconventional sphere-packing schemes open up possibilities to design materials with different properties. The challenge in soft materials is how to correlate complex phases built from spheres with the tunable parameters of chemical composition and molecular architecture. Here, we report a complete sequence of various highly ordered mesophases by the self-assembly of specifically designed and synthesized giant surfactants, which are conjugates of hydrophilic polyhedral oligomeric silsesquioxane cages tethered with hydrophobic polystyrene tails. We show that the occurrence of these mesophases results from nanophase separation between the heads and tails and thus is critically dependent on molecular geometry. Variations in molecular geometry achieved by changing the number of tails from one to four not only shift compositional phase boundaries but also stabilize F-K and quasicrystal phases in regions where simple phases of spheroidal micelles are typically observed. These complex self-assembled nanostructures have been identified by combining X-ray scattering techniques and real-space electron microscopy images. Brownian dynamics simulations based on a simplified molecular model confirm the architecture-induced sequence of phases. Furthermore, our results demonstrate the critical role of molecular architecture in dictating the formationmore » of supramolecular crystals with “soft” spheroidal motifs and provide guidelines to the design of unconventional self-assembled nanostructures.« less

Authors:

Yue, Kan ^[1]; Huang, Mingjun ^[1]; Marson, Ryan L. ^[2]; He, Jinlin ^[3]; Huang, Jiahao ^[1]; Zhou, Zhe ^[1]; Wang, Jing ^[1]; Liu, Chang ^[1]; Yan, Xuesheng ^[3]; Wu, Kan ^[1]; Guo, Zaihong ^[1]; Liu, Hao ^[1]; Zhang, Wei  ^[1];

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Ni, Peihong ^[3]; Wesdemiotis, Chrys ^[1]; Zhang, Wen-Bin ^[4]; Glotzer, Sharon C. ^[2]; Cheng, Stephen Z. D. ^[1]

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+ Show Author Affiliations

1. Univ. of Akron, OH (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States)
3. Soochow Univ., Suzhou (China)
4. Peking Univ., Beijing (China)

Publication Date:

Mon Nov 28 00:00:00 EST 2016

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; National Science Foundation (NSF); US Army Research Office; National Natural Science Foundation of China (NSFC); Natural Science Foundation of Jiangsu Province

OSTI Identifier:

1342238

Grant/Contract Number:  

AC05-00OR22725; DMR-1408872; W911NF-10-1-0518; 21304061; BK20130286; CHE-1308307

Resource Type:

Accepted Manuscript

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Volume: 113; Journal Issue: 50; Journal ID: ISSN 0027-8424

Publisher:

National Academy of Sciences

Country of Publication:

United States

Language:

ENGLISH

Subject:

36 MATERIALS SCIENCE; self-assembly; Frank–Kasper phases; quasicrystal phases; giant surfactants; POSS