Preparation of Novel W/O Gel-Emulsions and Their Application in the Preparation of Low-Density Materials

Chen, Xiangli; Liu, Kaiqiang; He, Panli; Zhang, Helan; Fang, Yu

doi:10.1021/la300856h

Cited by 59 publications

(56 citation statements)

References 37 publications

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“…Fourier transform infrared spectra were recorded with a Perkin Elmer Spectrum 100 ATR instrument. For each spectrum, 16 scans were conducted over a spectral range of 4000 to 600 cm ), 63 and showed that the tested gel systems were shear thinning. The rheological measurements were carried out after stabilizing the gels for 60 min in the sample holder at room temperature (25 o C).…”

Section: Methodsmentioning

confidence: 99%

Triggered formation of thixotropic hydrogels by balancing competitive supramolecular synthons

Liu

Steed

2013

Soft Matter

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Publisher's copyright statement: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Two component hydrogels have been obtained by formation of 1:1 complexes of bis(pyridyl urea)s with a range of dicarboxylic acids. The gels are thixotropic and undergo an assembly process in which short segments can reversibly assemble into an interconnected fibrous network. NMR and IR spectroscopic data suggest that the gelators form neutral gelator-acid complexes rather than salts. The use of dicarboxylic acids to trigger gelation in bis(pyridyl urea)s parallels analogous triggered gelation of metal 10 ions and halogen bond donors in related systems. IntroductionGels derived from low molecular weight gelators (LMWG) have experienced an explosion of interest in recent years. 14 The growing interest in their properties stems from their generally facile synthesis, their synthetic and structural versatility, and the possibility of adaptive or reversible gelation offered by the weak, dynamic supramolecular interactions holding the fibres together. 7 The 25 mechanism of the non-equilibrium self-assembly process involved in gel formation by LMWG is also fascinating from a fundamental viewpoint and is perhaps a more tractable problem in well-defined small molecules than in more conventional silica or biopolymer based hydrogels. Of particular current interest are 30 multicomponent gels. 25These systems may comprise stoichiometric co-gels in which two non-gelator components combine in a well-defined way to produce a gel-forming supermolecule, or they may be blends of LMWG (sometimes termed 'multi-gelator gels') that are individually gelators. 26-32 35 Some metallogels arising from metal cross-linking of gelating ligands, 4,6, 33 or anion influenced gels also fall into the broad category of multicomponent gels. [34][35][36] In previous work we have looked at triggered gelation in 'inhibited gelators', particularly pyridyl ureas. 37,38 Intramolecular CH O interactions coupled 40 with the good hydrogen bond acceptor ability of the pyridyl nitrogen atom make pyridyl ureas particularly poor gelators (Fig. 1b) 37, 39-41 because they cannot effectively form the typical urea -tape motif generally thought to be responsible for onedimensional fibre growth and hence gel formation (Fig. 1a). 42, 43 45 Addition of a co-gelator such as a metal ion 38,[44][45][46] or halogen bond donor 47 results in coordination to the pyridyl nitrogen atom hence freeing the urea functionality and switching the system from the urea-pyridyl hydrogen bonding motif to the ...

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Section: Methodsmentioning

confidence: 99%

Triggered formation of thixotropic hydrogels by balancing competitive supramolecular synthons

Liu

Steed

2013

Soft Matter

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“…Calixarene has been studies as a component of gelators. [37][38][39][40][41][42][43][44] Our group have reported two gel works based on calix [4]arene and for the rst time constructed a novel gelator with calix [4]arene fragment and two cholesterol. The rst work of our group based on calix [4]arene was that novel gelator was synthesized and used it prepared smart shearthixotropy gel in the mixture solvent of decane and acetonitrile.…”

Section: -18mentioning

confidence: 99%

“…Physical gels based on self-assembly structure of molecule because of potential application in drug/protein delivery, 1,2 oil spill recovery, [3][4][5] have become one of active frontiers of novel materials in recent years. Researcher struggled to prepare novel physical gel by bonding some functional groups and introducing extraordinary metal ions in gelator molecular or solvent.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and investigation of temperature-responsive calix[4]arene-based molecular gels

Cai

Rong

et al. 2017

RSC Adv.

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A novel calix [4]arene-based tetracholesteryl derivative was synthesized, and its gelation behaviours in 30 organic solvents were studied. It showed that 1 gelled long chain alkane, some of alcohol, kerosene, ethyl acetate benzene and toluene. Interestingly the gel of 1/kerosene possessed special property, which was that the mixture solution of the compound 1/kerosene heating for a while was put on the flat contact heater and formed a gel film at 25 C and 65 C. Unlike ordinary film, gel film had higher strength and toughness at 65 C, by contrast other was fragile and broken easily at 25 C, this phenomenon was few reported before. In order to explore the phenomenon, the mechanism of the gel of 1/kerosene was discussed by Scanning Electron Microscope (SEM), High Nuclear Magnetic Resonance (H NMR), Fourier Transform Infrared Spectrometer (IR) and micro-rheology. SEM revealed that the xerogel of 1/kerosene assembled network through some long and thick fibers at 65 C, with concentration reducing fibers become thin and its networks were clearly observed. In contrast the morphology of xerogel was porous at low concentration and was a bulk at high temperature system.According to EI data in micro-rheology, the gelation process could be divided into three stages at 65 C and they could be that some cholesterol segments in the gelator interacting with each other formed some small aggregation in the first stage, and other cholesterol section of the gelator sufficiently were cross-linked with time and assembled into large assembly in the second plateau. In the final moment the large assembly build gel network and the system of gel tended to stable. But there are two stages at low temperature and could be some cholesterol segments that didn't take part in assembly, which may be the cause that the performance of gel was fragile.

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“…For example, mixing speed (Gurevitch and Silverstein, 2010;Sturzenegger et al, 2012), particle concentration (Arditty et al, 2003;Binks and Whitby, 2004;Sturzenegger et al, 2012), particle wettability (Akartuna et al, 2008b;Bachinger and Kickelbick, 2010;Chuanuwatanakul et al, 2011;Haase et al, 2011), particle aspect ratio (Vandebril et al, 2010), particle roughness (San-Miguel and Behrens, 2012), and particle size (Binks and Lumsdon, 2001) have all been studied. Such wet emulsions can be shaped, extruded into forms or coated into sheets because of their measurable yield stress Chen et al, 2012). Once dried, the resulting highly porous green ceramics can be sintered, creating a ceramic foam with open cell microstructure and compressive strengths up to 13 MPa and porosities above 70 vol% (Akartuna et al, 2008a).…”

Section: Introductionmentioning

confidence: 99%

New composite separator pellet to increase power density and reduce size of thermal batteries

Mondy

Roberts

Grillet

et al. 2013

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We show that it is possible to manufacture strong macroporous ceramic films that can be backfilled with electrolyte to form rigid separator pellets suitable for use in thermal batteries. Several new ceramic manufacturing processes are developed to produce sintered magnesium oxide foams with connected porosities of over 80% by volume and with sufficient strength to withstand the battery manufacturing steps. The effects of processing parameters are quantified, and methods to imbibe electrolyte into the ceramic scaffold demonstrated. Preliminary single cell battery testing show that some of our first generation pellets exhibit longer voltage life with comparable resistance at the critical early times to that exhibited by a traditional pressed pellets. Although more development work is needed to optimize the processes to create these rigid separator pellets, the results indicate the potential of such ceramic separator pellets to be equal, if not superior to, current pressed pellets. Furthermore, they could be a replacement for critical material that is no longer available, as well as improving battery separator strength, decreasing production costs, and leading to shorter battery stacks for long-life batteries. 4

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Preparation of Novel W/O Gel-Emulsions and Their Application in the Preparation of Low-Density Materials

Cited by 59 publications

References 37 publications

Triggered formation of thixotropic hydrogels by balancing competitive supramolecular synthons

Triggered formation of thixotropic hydrogels by balancing competitive supramolecular synthons

Preparation and investigation of temperature-responsive calix[4]arene-based molecular gels

New composite separator pellet to increase power density and reduce size of thermal batteries

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