About Supramolecular Assemblies of π-Conjugated Systems

In recent years there has been immense interest in studying gels derived from low molecular mass gelators (supramolecular, or simply molecular gels). The motivation for this is not only to understand the fundamental aggregate structures in the gels at different length scales, but also to explore their potential for futuristic technological applications. Gels have been made sensitive to external stimuli like light and chemical entities by incorporating a spectroscopically active or a receptor unit as part of the gelator molecule. This makes them suitable for applications such as sensing and actuating. The diversity of gel structural architectures has allowed them to be utilized as templates to prepare novel inorganic superstructures for possible applications in catalysis and separation. Gels derived from liquid crystals (anisotropy gels) that can act as dynamically functional materials have been prepared, for example, for (re-writable) information recording. Supramolecular gels can be important in controlled release applications, in oil recovery, for gelling cryogenic fuels etc. They can also serve as media for a range of applications. This tutorial review highlights some of the instructive work done by various groups to develop smart and functional gels, and covers a wide spectrum of scientific interest ranging from medicine to materials science.

/pdf/supramolecular-gels-functions-and-uses-51lemkjn44.pdf

Supramolecular gels: Functions and uses

Functional π-Gelators and Their Applications

A Perspective is presented on the history and current understanding of molecular gels and the factors that must be considered to characterize them. The abilities of the most important structural, dynamic, and rheological tools available currently to provide the information necessary to follow the formation of a molecular gel from its initial sol phase and then to define it at different distance and time scales are discussed. Approaches to determining a priori when a molecule will gelate a selected liquid, as well as possible methodologies for overcoming current limitations in understanding molecular gels, are presented. Finally, some of the many potential and realized applications for these materials are enumerated.

The past, present, and future of molecular gels. What is the status of the field, and where is it going?

The history of human civilization is accompanied by the development of novel materials, from the period of natural stone, the bronze and iron age, to the modern times of synthetic materials and promising advanced materials. Liquid crystals (LCs) are one of such kind of materials that greatly infl uence our daily life, and which are not limited to displays such as TVs and personal computers. Being an intermediate phase of matter, LCs show characteristics of both controllable mobility of an isotropic liquid and ordered regularity of a crystalline solid. Combined with their photoresponsive properties, photocontrollable LC actuators have enabled a variety of applications in various fi elds, which include fl at panel displays, photonics, photo-driven devices, and more recently nanotechnology. The LC’s unique features provide soft materials in a liquid-crystalline state with interesting properties such as 1) selfassembly, 2) fl uidity with long-range order, 3) molecular and supramolecular cooperative motion (MCM and SMCM), 4) large birefringence and anisotropy in various physical properties (optical, mechanical, electrical and magnetic), 5) alignment change induced by external fi elds at surfaces and interfaces, and 6) deformation of LC elastomers (LCEs) in response to stimuli. [ 1–4 ]

Photocontrollable liquid-crystalline actuators.

Since 2,3-bis(n-decyloxy)anthracene (DDOA) is a good gelling agent for a large number of solvents including propylene carbonate (PC), the electrochemical properties of organogel electrolytes based on DDOA have been investigated. The presence of tetraalkylammonium salts in DDOA/PC gels is shown to preserve the three-dimensional network of DDOA fibers. In addition, at a given temperature, the conductivity is practically the same in the gel as in the corresponding solution with or without DDOA. The gelation temperature, Tgel, is slightly affected by the presence and nature of the salt. Thus, at 1M salt concentration, Tgel is increased by 9 °C with Et4NBF4 and decreased by 7 °C with Bu4NBF4, presumably because of a surfactant effect of the Bu4N+ cation. The electrochemical stability window of the liquid electrolyte is limited by the stability of DDOA, which displays the typical redox behavior of anthracene. However, in the gel state, DDOA is apparently protected within the fibers and the electrochemical stabi...

Organogel Electrolytes Based on a Low Molecular Weight Gelator: 2,3-Bis(n-decyloxy)anthracene

The UV absorption spectra of 2,3-didecyloxyanthracene (DDOA) recorded in methanol, ethanol, 1-propanol, acetonitrile and methylcyclohexane reveal interesting features: they show a striking contrast between the isotropic solution and the gel state where, at ambient temperature, a fine structure appears with an apparent bathochromic shift (Δν ≈ −700 cm−1), as observed in the solid state. Such an effect was mimicked by 2,3-dioxydi- (and -tri-) methyleneanthracenes in which the conformational mobility of the two juxtanuclear oxygen atoms is reduced in a manner similar to that assumed in the gel state. The fluorescence emission of DDOA (10−5 M) at very low temperature exhibits a loss of fine structure and a bathochromic shift, for the gel state, in agreement with the presence of aggregates; the excitation spectra were found to be superimposable upon the absorption spectra of the isotropic and gel phases, respectively. Solvent screening for DDOA gelling ability has shown that the most efficient solvents are CH3OH and CH3CN. From the phase transition diagram (temperatures of gel setting, Tgel, and gel melting, Tm, versus concentration), thermodynamic parameters were derived: ΔH0gel/kJ mol−1 = 
				−70 (CH3OH), −66 (CH3CN); ΔS0gel/(J K−1 mol−1 = −147 (CH3OH), −140 (CH3CN) and ΔG0gel/kJ mol−1 (at 300 K) ≈ −26 (CH3OH), −24 (CH3CN). These parameters attest to the good stability of these gel systems. Finally, the influence of the chain length (n = C7H15 to C12H25) on the efficiency of gel formation (or melting) was investigated in methanol, ethanol, acetonitrile and heptane. It emerges that, to form gels, n-decyl and n-undecyl were found to be the most suitable chains and methanol and ethanol the most efficient solvents. It should be noted that the ability to form gels in methanol at a concentration of 0.6 mM at ambient temperature qualifies DDOA as a supergelator.

Spectroscopic properties and gelling ability of a set of rod-like 2,3-disubstituted anthracenes

A new example of small molecular non-hydrogen bonding gelators for organic solvents

Water-in-oil-in-water (W/O/W) double emulsions were prepared and the rate of release of magnesium ions from the internal to the external aqueous phase was followed Sodium caseinate was used not only as a hydrophilic surface-active species but also as a chelating agent able to bind magnesium ions The release occurred without film rupturing (no coalescence) The kinetics of the release process depended on the location (in only one or in both aqueous compartments) and on the concentration of sodium caseinate The rate of release increased with the concentration of sodium caseinate in the external phase and decreased when sodium caseinate was present in the inner droplets The experiments were interpreted within the frame of a mean-field model based on diffusion, integrating the effect of ion binding The data could be adequately fitted by considering a time-dependent permeation coefficient of the magnesium ions across the oil phase Our results suggested that ion permeability was influenced by the state of

Impact of sodium caseinate concentration and location on magnesium release from multiple W/O/W emulsions.

2,3-Didecyloxyanthracene (DDOA) is able to gel a large variety of organic solvents at very low concentrations by forming a three-dimensional network of fibers. A vibrational assignment is proposed for the midinfrared absorptions of DDOA in the gel and solution states, showing that some out-of-plane vibrations of the anthracene group constitute pertinent local probes of the molecular organization in the three-dimensional supramolecular architecture. A model of the molecular arrangement of the DDOA molecules within the fibers is proposed from ab initio calculations combined with IR and fluorescence dichroism experiments performed on oriented bundles of aerogel fibers.

Molecular arrangement in the gel fibers of 2,3-didecyloxyanthracene (DDOA): A spectroscopic and theoretical approach

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Frédéric Placin

Author Tools

Chat about Author