Issue 45, 2021

Dependence of the liquid crystalline properties on the exactly controlled single-site functionalized density of mesogens focused on the alternating copolymer model

Abstract

Fluorinated liquid crystal polymers (FLCPs) with an AB/A2B-alternating sequence of fluorinated biphenyl moieties (FMs) along their backbones were constructed, where the anionic copolymerization of isoprene (Ip) with, mono-SiH and di-SiH functionalized 1,1-diphenylethylene (DPE) derivatives was performed to prepare alternating copolymer precursors with exactly controlled single-site densities of -SiH, i.e., alt-P(D-S/Ip) and alt-P(D-2S/Ip), respectively, followed by highly efficient hydrosilylation to introduce FMs into the repeating unit (DPE). Previous work indicated that the mesogenic properties were related to the distance between neighbouring mesogenic moieties in different polymerized units when the degree of polymerization (DP) of the copolymers was low. Hence, the present strategy provides a novel model to explore dependence of the mesogenic properties on the exactly controlled single-site functionalized density of mesogens (FMs) for the resulting alternating-templated FLCPs, which was achieved due to a quite low DP (11 for mono-SiH and 5 for di-SiH), while exhibiting a similar overall concentration of FMs along backbones bearing a similar number of Si–H groups. The results show that the polarized optical textures and the temperature range of mesogenic phase formation (ΔT) varied remarkably between A2B-alternating (ΔT = 104 °C) and AB-alternating (ΔT = 23 °C) FLCPs; in particular, the variation in phase transition temperature is possibly a result of exactly controlled single-site functionalized density. Herein, a novel morphological aggregation model is proposed to increase the comprehension of how the exactly controlled single-site functionalized density of FMs arranged within the small scale of polymer chains directs molecular packing and interactions between them, thereby enriching the diversity of molecular interactions.

Graphical abstract: Dependence of the liquid crystalline properties on the exactly controlled single-site functionalized density of mesogens focused on the alternating copolymer model

Supplementary files

Article information

Article type
Paper
Submitted
30 Sep 2021
Accepted
30 Oct 2021
First published
01 Nov 2021

Polym. Chem., 2021,12, 6561-6568

Dependence of the liquid crystalline properties on the exactly controlled single-site functionalized density of mesogens focused on the alternating copolymer model

R. Zhang, X. Li, H. Ma, L. Han, C. Li, S. Zhang, H. Bai and Y. Li, Polym. Chem., 2021, 12, 6561 DOI: 10.1039/D1PY01310F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements