Liquid crystal anchoring transitions and weak anchoring interface formation at surfaces created by uniquely designed acrylate copolymers

Rijeesh, K.; Higuchi, Hiroki; Okumura, Yasushi; Yamamoto, Jun; Kikuchi, Hirotsugu

doi:10.1016/j.polymer.2016.12.012

Cited by 9 publications

(7 citation statements)

References 27 publications

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“…This can be possible only if the anchoring energy between the polymer and LC is weaker. When the anchoring energy between the LC and polymer is weak, LC molecules respond to an applied electric field easily and thereby reduce the voltage required to switch the system [55,56]. Under such a condition, however, the LC molecules recover to its original state slowly after the removal of the applied field, resulting in the increase of decay time.…”

Section: Resultsmentioning

confidence: 99%

High-Performance Polymer Dispersed Liquid Crystal Enabled by Uniquely Designed Acrylate Monomer

et al. 2020

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The widespread electro–optical applications of polymer dispersed liquid crystals (PDLCs) are hampered by their high-driving voltage. Attempts to fabricate PDLC devices with low driving voltage sacrifice other desirable features of PDLCs. There is thus a clear need to develop a method to reduce the driving voltage without diminishing other revolutionary features of PDLCs. Herein, we report a low-voltage driven PDLC system achieved through an elegantly simple and uniquely designed acrylate monomer (A3DA) featuring a benzene moiety with a dodecyl terminal chain. The PDLC films were fabricated by the photopolymerization of mono- and di-functional acrylate monomers (19.2 wt%) mixed in a nematic liquid crystal E7 (80 wt%). The PDLC film with A3DA exhibited an abrupt decline of driving voltage by 75% (0.55 V/μm) with a high contrast ratio (16.82) while maintaining other electro–optical properties almost the same as the reference cell. The response time was adjusted to satisfactory by tuning the monomer concentration while maintaining the voltage significantly low (3 ms for a voltage of 0.98 V/μm). Confocal laser scanning microscopy confirmed the polyhedral foam texture morphology with an average mesh size of approximately 2.6 μm, which is less in comparison with the mesh size of reference PDLC (3.4 μm), yet the A3DA-PDLC showed low switching voltage. Thus, the promoted electro–optical properties are believed to be originated from the unique polymer networks formed by A3DA and its weak anchoring behavior on LCs. The present system with such a huge reduction in driving voltage and enhanced electro–optical performance opens up an excellent way for abundant perspective applications of PDLCs.

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Section: Resultsmentioning

confidence: 99%

High-Performance Polymer Dispersed Liquid Crystal Enabled by Uniquely Designed Acrylate Monomer

et al. 2020

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“…In our previous report, we have demonstrated the practicability of using uniquely designed side‐chain non‐liquid crystalline acrylate copolymers for weak anchoring of nematic liquid crystals . These copolymers feature a mesogenic unit (A6CN or A6OC6H13) and a methyl acrylate non‐mesogenic part.…”

Section: Resultsmentioning

confidence: 99%

“…A variety of mixing ratios were employed to achieve optimum condition for successful BP stabilization by varying the mono‐functional monomers A6CN or A6OC6H13 (Figure ) and dodecyl acrylate (DA). The DA replaced the role of methyl acrylate in our previous copolymers designs as a non‐mesogenic unit, in light of the fact that methyl acrylate cannot stabilize BPLC. The percentage composition of LC mixtures (JC+5CB), chiral dopant (ISO(6OBA)2), bifunctional monomer (RM257) and initiator (DMPAP) were kept identical for all the experiments (Figure S1).…”

Section: Resultsmentioning

confidence: 99%

“…We have recently shown, for the first time, a unique method of weak anchoring for nematic liquid crystals, where LC molecules experienced a weak anchoring on uniquely designed acrylate copolymers surfaces . Here, we discuss our preliminary studies to investigate whether these weak anchoring interface inducing copolymer designs would acts as a weak anchoring surface for polymer‐stabilized blue phase liquid crystal to reduce the driving voltage of PS‐BPLCs, while preserving the other electro‐optical properties of blue phase liquid crystals.…”

Section: Introductionmentioning

confidence: 99%

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Weak Anchoring Interface Inducing Acrylate Copolymer Designs for High‐Performance Polymer‐Stabilized Blue Phase Liquid Crystal Displays

et al. 2017

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Polymer-stabilized blue phase liquid crystal (PS-BPLC) is emerging as a strong competitor for next-generation liquid crystal displays and optoelectronic devices. However, the realization of technologies built on PS-BPLC requires lowering of driving voltage without sacrificing other desirable properties of blue phase liquid crystals. Here, we present a new method for voltage reduction in PS-BPLC based on the stabilization of BPLC with weak anchoring interface inducing acrylate monomers. This method provides significant voltage reduction while maintaining the electro-optical performance of BPLCs at the same time. We believe that this approach has a great potential in developing high-performance photonic devices and displays based on liquid crystals.[a] Dr.

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“…Generally, it is difficult to achieve weak anchoring. Studies until now have reported that surface modification by a liquid layer and a flexible oligomer/polymer layer can weaken the azimuthal anchoring strength by shielding the interaction between the LC molecules and their strongly anchored solid surfaces. − A polymer coating stabilizes the so-called stealth layer and ensures that it stays on the surface.…”

Section: Introductionmentioning

confidence: 99%

Near-Zero Azimuthal Anchoring of Liquid Crystals Assisted by Viscoelastic Bottlebrush Polymers

Kinose

Sakakibara²,

Sato

et al. 2021

ACS Appl. Polym. Mater.

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In this article, we revealed the mechanism of weak anchoring properties of liquid crystals (LCs) on cross-linked films of bottlebrushes consisting of poly(hexyl methacrylate) (PHMA) and poly(ethyl methacrylate) (PEMA). First, azimuthal anchoring coefficients, A 2 , of a LC were estimated using these two systems from the voltage−transmittance curves at different temperatures. The PHMA and PEMA systems showcased a temperaturedependent weak anchoring property, with A 2 decreasing as the temperature was increased. Second, the degree of swelling of these two systems (with cross-linked films) by the LCs was determined and compared with the phase diagrams of the corresponding mixtures without cross-linking, suggesting that the relaxation dynamics of side chains of bottlebrushes was retained even after the cross-linking. Finally, rheological measurements were conducted for the LC/bottlebrush mixtures to discuss the dynamics of the LCswollen cross-linked bottlebrush films, which clearly demonstrated the relaxation behavior of the side chains. Assuming the time scale for the determination of A 2 , the characteristic temperature corresponding to the side-chain motion was reasonably correlated with the decreasing temperature behavior of A 2 . As a consequence, weak anchoring could be explained by the polymer chain dynamics, which was revealed to be accelerated by the bottlebrush architecture as well as the swelling with LCs, depending on the affinity of the bottlebrush component with the target LC.

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Liquid crystal anchoring transitions and weak anchoring interface formation at surfaces created by uniquely designed acrylate copolymers

Cited by 9 publications

References 27 publications

High-Performance Polymer Dispersed Liquid Crystal Enabled by Uniquely Designed Acrylate Monomer

High-Performance Polymer Dispersed Liquid Crystal Enabled by Uniquely Designed Acrylate Monomer

Weak Anchoring Interface Inducing Acrylate Copolymer Designs for High‐Performance Polymer‐Stabilized Blue Phase Liquid Crystal Displays

Near-Zero Azimuthal Anchoring of Liquid Crystals Assisted by Viscoelastic Bottlebrush Polymers

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