Liquid crystal alignment behaviors and wetting properties of polymer blend surfaces

Sohn, Eun‐Ho; Lee, Mongryong; Song, Kigook

doi:10.1007/s13233-013-1096-4

Cited by 7 publications

(3 citation statements)

References 44 publications

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“…demonstrated that, a mixed monolayer composed of long and short chain alkylsilane performed on glass substrates was more effective in bringing about successful homeotropic anchoring of LCs compared to a SAM composed of a single alkylsilane molecule 18 . LC alignment studies over blend polymer surfaces were also reported 19 . Further, a photoswitchable azosilane monolayer on a glass/ITO substrate was also used for the LC alignment 20 .…”

Section: Introductionmentioning

confidence: 99%

Vertical Alignment of Liquid Crystals Over a Functionalized Flexible Substrate

Sivaranjini

Mangaiyarkarasi

Ganesh

et al. 2018

Sci Rep

162

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A simple and effective approach for vertical alignment of liquid crystals (LCs) over a functionalized transparent flexible substrate is described. Surface characterization of this commercially available plastic substrate through X-ray photoelectron spectroscopy (XPS) and attenuated total reflection infrared spectroscopy (ATR-IR) indicated that cellulose acetate is main component of the transparent substrate. This substrate was chemically functionalized with a suitable LC compound. A trimethoxysilane terminated new rod-shaped mesogen is synthesized and covalently attached to the pre-treated film through silane condensation reaction. LC functionalization of the polymer film is confirmed through contact angle (CA), atomic force microscopy (AFM), XPS and ATR-IR spectroscopy studies. Versatility of the LC modified flexible substrates for the alignment of bulk LC sample at substrate-LC interface was assessed for nematic (N) and smectic A (SmA) phases. Remarkably, LC functionalized cellulose acetate films were found to be highly efficient in assisting a perfect homeotropic alignment of LCs (for both, a room temperature N and a high temperature SmA phase) over the entire area of the LC sample under observation indicating their superior aligning ability in comparison to their unmodified and octadecyltrimethoxysilane (OTS) modified counterparts. The demonstrated method of surface modification of flexible polymer film is easy, surface modified substrates are stable for several months, retained their aligning ability intact and more importantly they are reusable with maximum delivery.

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Section: Introductionmentioning

confidence: 99%

Vertical Alignment of Liquid Crystals Over a Functionalized Flexible Substrate

Sivaranjini

Mangaiyarkarasi

Ganesh

et al. 2018

Sci Rep

162

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“…A similar trend of reduced contact angle values with increasing PEG molecular weight was also observed in other studies. [31][32][33]…”

Section: Contact Angle Data Of Hydrogel Filmsmentioning

confidence: 99%

Examination of fabrication conditions of acrylate-based hydrogel formulations for doxorubicin release and efficacy test for hepatocellular carcinoma cell

Bayramoğlu

Gozen

Ersoy

et al. 2014

Journal of Biomaterials Science, Polymer Edition

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The objective of the present study was to develop 2-hydroxypropyl methacrylate-co-polyethylene methacrylate [p(HPMA-co-PEG-MEMA)] hydrogels that are able to efficiently entrap doxorubicin for the application of loco-regional control of the cancer disease. Systemic chemotherapy provides low clinical benefit while localized chemotherapy might provide a therapeutic advantage. In this study, effects of hydrogel properties such as PEG chains length, cross-linking density, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. In addition, the characterization of the hydrogel formulations was conducted with swelling experiments, permeability tests, Fourier transform infrared, SEM, and contact angle studies. In these drug-hydrogel systems, doxorubicin contains amine group that can be expected a strong Lewis acid-base interaction between drug and polar groups of PEG chains, thus the drug was released in a timely fashion with an electrostatic interaction mechanism. It was observed that doxorubicin release from the hydrogel formulations decreased when the density of cross-linking, and drug/polymer ratio were increased while an increase in the PEG chains length of the macro-monomer (i.e. PEG-MEMA) in the hydrogel system was associated with an increase in water content and doxorubicin release. The biocompatibility of the hydrogel formulations has been investigated using two measures: cytotoxicity test (using lactate dehydrogenase assay) and major serum proteins adsorption studies. Antitumor activity of the released doxorubicin was assessed using a human SNU398 human hepatocellular carcinoma cell line. It was observed that doxorubicin released from all of our hydrogel formulations which remained biologically active and had the capability to kill the tested cancer cells.

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“…The phenomenon that liquid crystal exhibits a preferential orientation at interfaces, called surface anchoring, has been studied for many years, which includes homeotropic anchoring, planar unidirectional anchoring, and planar degenerate anchoring. [1,2] Such a kind of investigation, such as surfaceinduced wetting [3][4][5] of thermotropic liquid crystals, is of special importance because of its technological applications. [6,7] To describe this interfacial interaction, a simple phenomenological expression, later called RP-form, was given by Rapini and Papoular (RP) [8] in 1969, which interpreted the interfacial energy per unit area for a one-dimensional deformation as g s = A sin 2 θ /2, where A and θ are the anchoring strength parameter and the angle between the easy direction 𝑛 and the orientation of the director at the interface 𝑛 0 respectively.…”

Section: Introductionmentioning

confidence: 99%

Quartic coupling and its effect on wetting behaviors in nematic liquid crystals

Zeng¹,

Merlitz²,

Wu³

2015

Chinese Phys. B

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Based on the fact that rubbed groove patterns also affect the anchoring of liquid crystals at substrates, a quartic coupling is included in constructing the surface energy for a liquid crystal cell. The phase diagram and the wetting behaviors of the liquid crystal cell, bounded by surfactant-laden interfaces in a magnetic field perpendicular to the substrate are discussed by taking the quartic coupling into account. The nematic order increases at the surface while it decreases in the bulk as a result of the introduction of quartic substrate-liquid crystal coupling, indicating that the groove anchoring makes the liquid crystal molecules align more orderly near the substrate than away from it. This causes a different wetting behavior: complete wetting.

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Liquid crystal alignment behaviors and wetting properties of polymer blend surfaces

Cited by 7 publications

References 44 publications

Vertical Alignment of Liquid Crystals Over a Functionalized Flexible Substrate

Vertical Alignment of Liquid Crystals Over a Functionalized Flexible Substrate

Examination of fabrication conditions of acrylate-based hydrogel formulations for doxorubicin release and efficacy test for hepatocellular carcinoma cell

Quartic coupling and its effect on wetting behaviors in nematic liquid crystals

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