Phase separation and dewetting of polymer dispersed liquid crystal (PDLC) thin films on flat and patterned substrates

Dhara, Palash; Mukherjee, Rabibrata

doi:10.1016/j.molliq.2021.117360

Cited by 14 publications

(3 citation statements)

References 55 publications

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“…Furthermore, it can control the UV-light intensity to modulate the micro-morphology of the sample to realize differentiated electro-optical properties. Typically, PDLC films tend to require low threshold voltages, fast response times associated with on/off state transition, and high levels of contrast ratios for on/off transmittance to realize the demands of safety in the application process [ 38 , 39 , 40 ]. As for contemporary PDLC devices, drawbacks such as a high driving voltage, low contrast ratio, and inferior mechanical applicability are still restricting their further deployment and must be carefully considered.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Application of Polymer-Dispersed Liquid Crystal Film with Step-Driven Display Capability

Lin,

Zhao,

Jiao

et al. 2024

Molecules

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The realization of multifunctional advanced displays with better electro-optical properties is especially crucial at present. However, conventional integral full drive-based transparent display is increasingly failing to meet the demands of the day. Herein, partitioned polymerization as a novel preparation method was introduced innovatively into polymer-dispersed liquid crystals (PDLC) for realizing a step-driven display in agreement with fluorescent dye to solve the above drawback. At first, the utilization of fluorescent dye to endow the PDLC film with fluorescent properties resulted in a reduction in the saturation voltage of the PDLC from 39.7 V to 25.5 V and an increase in the contrast ratio from 58.4 to 96.6. Meanwhile, the experimental observations and theoretical considerations have elucidated that variation in microscopic pore size can significantly influence the electro-optical behavior of PDLC. Then, the step-driven PDLC film was fabricated through the exposure of different regions of the LC cell to different UV-light intensities, resulting in stepwise voltage–transmittance (V–T) responses of the PDLC film for the corresponding regions. Consequently, under appropriate driving voltages, the PDLC can realize three different states of total scattering, semi-transparent and total transparent, respectively. In addition, the PDLC film also embodied an outstanding anti-aging property and UV-shielding performance, which makes it fascinating for multifunctional advanced display applications.

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Section: Introductionmentioning

confidence: 99%

Preparation and Application of Polymer-Dispersed Liquid Crystal Film with Step-Driven Display Capability

Lin,

Zhao,

Jiao

et al. 2024

Molecules

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“…Various experimental techniques have been developed to determine the LC phase transition points with high accuracy, such as differential scanning calorimetry (DSC), dynamic mechanical analysis, X-ray diffraction, etc. However, all of these techniques rely on advanced instruments and specific experimental conditions, making them less applicable for in situ measurements, such as observation of the self-assembly processes of LC block copolymers and homopolymers in solution-state, − phase separation processes, detections of fracture and self-healing process of LC elastomers, dynamic stimulus-response process of LC networks, etc.…”

Section: Introductionmentioning

confidence: 99%

Accurate Detection of Liquid Crystalline Transitions of Cholesteryl-Containing Homopolymers via the Aggregation-Induced Emission of Tetraphenylethylene

He,

Li,

Luo

et al. 2023

Macromolecules

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Since the discovery of the aggregation-induced emission (AIE) phenomenon, it has been widely applied in various fields. Particularly, the emission of AIE moieties is highly sensitive to their molecular packing and very useful to reveal the chain movement of polymers in real time. Herein, we report our attempts to use tetraphenylethylene (TPE) to characterize the liquid crystalline (LC) transitions of cholesteryl-containing homopolymers by monitoring their emission intensity variations versus temperature. However, unlike similar cases aiming for other characteristics of polymers, directly blending TPE molecules into homopolymer matrices markedly disrupted the LC transition. Although the fluorescence intensity variations could decently reveal the glass transition temperature (T g), it exhibited absolutely no sensitivity to the LC transition process. Meanwhile, if the TPE moieties were labeled onto one of the chain ends of homopolymers, the LC transition was untouched, and the transition points determined were identical to those obtained from standard techniques.

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“…Indeed, surface-induced morphological phase separation in an immiscible polymer blend thin film spin cast from a common solvent has long been explored and has garnered considerable attention due to its potential applications in areas such as dielectric coatings, the modulation of optical and wetting characteristics of surfaces, and gaining insights into how confinement affects phase separation (Tu, et al, 2019a;Tu, et al, 2019;Bhandaru, 2020;Dhara and Mukherjee, 2021;Saleem et al, 2023). Polystyrene and poly(metha methacrylate) (PMMA) immiscible blends are among the systems that have been studied most extensively (Das et al, 2020;Guo and Ren, 2021;Mrđenović et al, 2022;Cai et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Fabrication of micropatterned thin films through controlled phase separation of polystyrene/polydimethylsiloxane blends by spin coating

Agarwal,

Lu,

Sarkar

2023

Front. Soft Matter

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In this study, we blended two readily available polymers, polydimethylsiloxane (PDMS), a semi-crystalline polymer, and polystyrene (PS), an amorphous polymer, both having widely varying physical properties. The blend is then spin coated to form a thin film. We investigated the effects of relative polymer concentration, spin coating speed, and environmental factors, such as temperature, on the ultimate morphologies of the phase-separated thin films. It was found that it is possible to regulate the morphologies of the thin films to achieve desirable microstructures such as spherical droplets, holes, bi-continuous lamellar structures, and tubules by controlling the fabrication conditions. The polymer blend films with higher PS concentrations were shown to form a bilayer system with an upper PS-rich layer due to the thermodynamic instability of the film caused by the rapid evaporation of solvent, while films with higher PDMS concentrations exhibited cohesive forces that engendered microtubule formation and led to high surface roughness.

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Phase separation and dewetting of polymer dispersed liquid crystal (PDLC) thin films on flat and patterned substrates

Cited by 14 publications

References 55 publications

Preparation and Application of Polymer-Dispersed Liquid Crystal Film with Step-Driven Display Capability

Preparation and Application of Polymer-Dispersed Liquid Crystal Film with Step-Driven Display Capability

Accurate Detection of Liquid Crystalline Transitions of Cholesteryl-Containing Homopolymers via the Aggregation-Induced Emission of Tetraphenylethylene

Fabrication of micropatterned thin films through controlled phase separation of polystyrene/polydimethylsiloxane blends by spin coating

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