Birefringent physical gels of N-(4-n-alkyloxybenzoyl)-l-alanine amphiphiles in organic solvents: The role of hydrogen-bonding

Patra, Trilochan; Pal, Amit; Dey, Joykrishna

doi:10.1016/j.jcis.2009.12.003

Cited by 24 publications

(19 citation statements)

References 66 publications

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“…This shi of 1 H NMR signal evidenced a change in the microenvironment of amphiphiles due to p-p stacking interaction among the tyrosine segment. 42 Apart from the 1 H NMR study, we also studied the mode of p-p stacking interaction during gelation using UV-vis technique. According to the literature, the H-stacking of the aromatic segment is generally manifested to a blue shi of the respective p-p* transition.…”

Section: Gelation Study Of Amphiphilic Gelatormentioning

confidence: 99%

Gelation of amino acid-based amphiphiles in water-based mixed solvent systems: reusable catalytic templates for nanostructured silica and silica–zirconia photocatalyst

et al. 2013

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We describe a gelation study of a series of different fatty acid-amino acid conjugated amphiphiles in various mixed solvent systems with water. Field emission scanning electron microscopy (FESEM), polarized optical microscopy (POM) and X-ray diffraction (XRD) study reveals that the self-organization of the amphiphile molecules in the mixed solvent leads to the formation of crystalline fibers, which form the opaque white gel. This amino acid amphiphile-based gel acts as a catalyst as well as a template for the hydrolysis/condensation of tetraethoxysilane (TEOS) to silica and forms a composite gel. The methanol extraction of the opaque white as-prepared composite gel results in the formation of a transparent nanostructured silica gel. The recovered amphiphilic gelator, after a methanol wash, can be reused for preparing a gel, which can subsequently be used as a catalyst to prepare a nanostructured silica gel again. The FESEM study confirms that the formed nanostructured silica gel is made up of spherical silica nanoparticles. We also extend this gel-based catalysis strategy to prepare silica-zirconia mixed oxide nanostructures. TEM examination reveals the formation of spherical silica-zirconia nanoparticle of high surface area as confirmed through BET surface area measurement. Finally, the photocatalytic activity of silica-zirconia mixed oxide is investigated towards methylene blue degradation. The mixed oxide shows higher photocatalytic efficiency than neat zirconia nanostructures.

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Section: Gelation Study Of Amphiphilic Gelatormentioning

confidence: 99%

Gelation of amino acid-based amphiphiles in water-based mixed solvent systems: reusable catalytic templates for nanostructured silica and silica–zirconia photocatalyst

et al. 2013

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“…The rise in temperature increased the surface active energy with a subsequent increase in the mobility of self‐assembled aggregates formed by the gelator molecules. This resulted in the interference of absorbed thermal energy with the molecular interactions amongst self‐assembled aggregates 53. This in turn resulted in the disruption of the networked structure thereby causing the system to flow freely (Fig.…”

Section: Resultsmentioning

confidence: 99%

Span‐60‐based organogels as probable matrices for transdermal/topical delivery systems

Behera

Patil

Sagiri

et al. 2011

J of Applied Polymer Sci

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The current study describes the preparation and characterization of thermoreversible span-60 and sunflower oil (SO)-based organogels as a matrix for drug delivery. Effect of gelator concentration on the properties of the organogels was studied by physical property evaluation, stability, light microscopy, FTIR spectroscopy, XRD, thermal analysis, pH, and hemocompatibility studies. The drug release kinetics and antimicrobial efficacy of the salicylic acid loaded organogels were studied. The rate of gelation of the gels was found to be quicker in organogels with higher gelator proportions. The gels were inherently stable when stored below 25 C. The micrographs indicated the presence of needle-shaped crystals which formed aggregates resulting in the formation of three-dimensional networked structures. FTIR indicated intermolecular hydrogen bonding amongst SO and span-60 molecules responsible for the gelation. There was an increase in the crystallinity and the melting point of the organogels as the proportion of the organogelator was increased. The pH of the organogels indicated nonirritant nature of the gels, which were also found to be hemocompatible. The release of SA from organogels followed Higuchian kinetics and showed prolonged antimicrobial activity. The preliminary results indicated that the organogels may be tried as a matrix for controlled drug delivery.

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“…Such birefringence has already been reported for af ew examples of supramolecular gels. [25,47,48] Noteworthy,t he defined texture is retained within the xerogel obtained upon complete dehydration of the gel phase. Indeed, as observed in Figure2,t he POM micrograph of ad eposited gel (Figure 2a), left for severalh ours on aw arm hot-stage (30 8C) to undergo complete dehydration, shows, under the polarized microscope, identicalf eatures in texture with exception of well-defined cracks owing to partial shrinkage that occurred during drying of the gel phase ( Figure 2b).…”

Section: Resultsmentioning

confidence: 99%

“…An intense and homogeneous birefringence was observed, indicative of an anisotropic arrangement of the molecules in ordered structures. Such birefringence has already been reported for a few examples of supramolecular gels . Noteworthy, the defined texture is retained within the xerogel obtained upon complete dehydration of the gel phase.…”

Section: Resultsmentioning

confidence: 99%

High Order in a Self‐Assembled Iridium(III) Complex Gelator Towards Nanostructured IrO₂ Thin Films

Scarpelli

Ionescu

Aiello

et al. 2017

Chemistry An Asian Journal

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The preparation and characterization of a new metallogelator based on the Ir discrete cyclometalated complex [(ppy) Ir(bpy)](CH CH OCH CO ) are reported, where H(ppy) is 2-phenylpiridine and bpy is 2,2'-bipyridine, which is used as an ancillary ligand. The compound is able to self-assemble in water in a range of concentrations between 3 % and 6 % w/w, creating a luminescent ordered supramolecular gel. The gel and xerogel architectures were investigated through polarized optical microscopy (POM), SEM and TEM microscopies coupled with powder X-ray diffraction. The gel supramolecular organization is characterized by columnar tetragonal strands, already present at high dilution conditions, of cations surrounded by counteranions. These strands, in turn, are self-assembled in an oblique columnar cell upon gelification. The xerogel thin films obtained upon complete dehydration maintained the gel supramolecular order and can be used as a precursor for the preparation of nanostructured IrO thin films.

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Birefringent physical gels of N-(4-n-alkyloxybenzoyl)-l-alanine amphiphiles in organic solvents: The role of hydrogen-bonding

Cited by 24 publications

References 66 publications

Gelation of amino acid-based amphiphiles in water-based mixed solvent systems: reusable catalytic templates for nanostructured silica and silica–zirconia photocatalyst

Gelation of amino acid-based amphiphiles in water-based mixed solvent systems: reusable catalytic templates for nanostructured silica and silica–zirconia photocatalyst

Span‐60‐based organogels as probable matrices for transdermal/topical delivery systems

High Order in a Self‐Assembled Iridium(III) Complex Gelator Towards Nanostructured IrO₂ Thin Films

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Birefringent physical gels of N-(4-n-alkyloxybenzoyl)-l-alanine amphiphiles in organic solvents: The role of hydrogen-bonding

Cited by 24 publications

References 66 publications

Gelation of amino acid-based amphiphiles in water-based mixed solvent systems: reusable catalytic templates for nanostructured silica and silica–zirconia photocatalyst

Gelation of amino acid-based amphiphiles in water-based mixed solvent systems: reusable catalytic templates for nanostructured silica and silica–zirconia photocatalyst

Span‐60‐based organogels as probable matrices for transdermal/topical delivery systems

High Order in a Self‐Assembled Iridium(III) Complex Gelator Towards Nanostructured IrO2 Thin Films

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High Order in a Self‐Assembled Iridium(III) Complex Gelator Towards Nanostructured IrO₂ Thin Films