Title: Nucleation and growth of blue phase liquid crystals on chemically-patterned surfaces: a surface anchoring assisted blue phase correlation length

Abstract

In condensed matter, the correlation length is an essential parameter which describes the distance over which a material maintains its structural properties. In liquid crystals, for the orientational order parameter this characteristic length is of the order of nanometers, while in solid crystals it can extend to macroscopic length scales. Here, we report the measurement of the correlation length, or persistence length, of the crystallographic orientation of blue phases (BPs)—chiral liquid crystals with long-range 3D-crystalline structures and submicron-sized lattice-parameters. These materials exhibit phase transformations that have been identified as the liquid analog of crystal-crystal martensitic transformations. In this work, we use liquid epitaxial growth to achieve spontaneous BP-crystal nucleation and subsequent growth. Specifically, we design patterned substrates made of a binary array of regions with different liquid crystal anchoring, which facilitate a uniform nucleation and growth of BP-crystals with (100)-lattice orientation and a simple cubic symmetry. Furthermore, our results indicate that this simple cubic BP, the so-called blue phase II (BPII), forms first on the patterned surface, thereby propagating the growth of domains in directions parallel or perpendicular to the patterned regions. These results are used to understand the emergence of a surface anchoring assisted BPII-correlation length, taken as themore » distance over which the BP preserves its lattice orientation, as a function of time and pattern characteristics. We found that BPII single crystals can be achieved on patterned regions whose lateral dimensions are equal to or larger than 10 μm, consistent with our measurements of the BPII-correlation length. This newly acquired understanding of the role of surfaces on the formation of BPs is then used to design processes that permit formation of macroscopically large mono-domain, single-crystal BPs by relying on significantly reduced patterned areas (only part of the area is patterned), a feature that could benefit the applications of this intriguing class of materials.« less

Authors:

Li, Xiao  ^[1];

• Search DOE PAGES for author "Li, Xiao"
• Search DOE PAGES for ORCID "0000-0003-3456-1933"

Park, Kangho ^[2]; Guzmán, Orlando ^[3]; Martínez-González, José A.  ^[4];

• Search DOE PAGES for author "Martínez-González, José A."
• Search DOE PAGES for ORCID "0000-0001-7257-8889"

Dolan, James A. ^[5]; de Pablo, Juan J.  ^[6];

• Search DOE PAGES for author "de Pablo, Juan J."
• Search DOE PAGES for ORCID "0000-0002-3526-516X"

Nealey, Paul F. ^[6]

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+ Show Author Affiliations

1. Univ. of North Texas, Denton, TX (United States)
2. Univ. of Chicago, IL (United States); Samsung Electronics Co., Ltd, Gyeonggi-Do (Korea, Republic of)
3. Univ. of Chicago, IL (United States); Univ. Autónoma Metropolitana Iztapalapa (Mexico)
4. Univ. Autónoma de San Luis Potosí (Mexico)
5. Univ. of Cambridge (United Kingdom)
6. Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Lemont, IL (United States)

Publication Date:

Fri May 28 00:00:00 EDT 2021

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; University of Chicago, Materials Research Science & Engineering Center (MRSEC); National Science Foundation (NSF)

OSTI Identifier:

1868961

Alternate Identifier(s):

OSTI ID: 1786236

Grant/Contract Number:  

AC02-06CH11357; DMR-1420709

Resource Type:

Accepted Manuscript

Journal Name:

Molecular Systems Design & Engineering

Additional Journal Information:

Journal Volume: 6; Journal Issue: 7; Journal ID: ISSN 2058-9689

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; blue phase liquid crystal; directed self-assembly; chemical pattern; crystal growth; correlation length