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Artykuły w czasopismach na temat "Supramolecular Gelator"
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Alegre-Requena, Juan V., Marleen Häring, Isaac G. Sonsona, Alex Abramov, Eugenia Marqués-López, Raquel P. Herrera i David Díaz Díaz. "Synthesis and supramolecular self-assembly of glutamic acid-based squaramides". Beilstein Journal of Organic Chemistry 14 (6.08.2018): 2065–73. http://dx.doi.org/10.3762/bjoc.14.180.
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We describe the preparation and characterization of two new unsymmetrical squaramide-based organogelators. The synthesis of the compounds was carried out by subsequent amine condensations starting from dimethyl squarate. The design of the gelators involved a squaramide core connected on one side to a long aliphatic chain and on the other side to a glutamic acid residue. The gelator bearing the free carboxylic groups showed a lower gelation capacity than its precursor diester derivative. Some selected gels were further studied by infrared spectroscopy, rheology and electron microscopy. Critical gelation concentrations and gel-to-sol transition temperatures were also determined for each case. In addition, the superior squaramide diester gelator was compared with an analogue triazole-based gelator in terms of critical gelation concentration, gelation kinetics and thermal phase transition.
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Haldar, Saubhik, i Koninika Karmakar. "A systematic understanding of gelation self-assembly: solvophobically assisted supramolecular gelation via conformational reorientation across amide functionality on a hydrophobically modulated dipeptide based ambidextrous gelator, N-n-acyl-(l)Val-X(OBn), (X = 1,ω-amino acid)". RSC Advances 5, nr 81 (2015): 66339–54. http://dx.doi.org/10.1039/c5ra10209j.
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Gelator backbone conformational flexibility plays an important role in a supramolecular self-assembly which is synergistically assisted by solvophobic interaction leading to a gelation of three sets of hydrophobically modulated dipeptidic gelators.
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Yin, Chunyu, Fengrui Jiang, Bao Li i Lixin Wu. "Multiple modulations for supramolecular hydrogels of bola-form surfactants bearing rigid and flexible groups". Soft Matter 15, nr 25 (2019): 5034–41. http://dx.doi.org/10.1039/c9sm00782b.
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Supramolecular hydrogels of bola-form surfactants were modulated by light irradiation and chemical additives to achieve reversible and unidirectional transitions between the gel and sol while a non-gelator boosts the gelation of the gelators.
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Ghosh, Dipankar, Matthew T. Mulvee i Krishna K. Damodaran. "Tuning Gel State Properties of Supramolecular Gels by Functional Group Modification". Molecules 24, nr 19 (25.09.2019): 3472. http://dx.doi.org/10.3390/molecules24193472.
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The factors affecting the self-assembly process in low molecular weight gelators (LMWGs) were investigated by tuning the gelation properties of a well-known gelator N-(4-pyridyl)isonicotinamide (4PINA). The N―H∙∙∙N interactions responsible for gel formation in 4PINA were disrupted by altering the functional groups of 4PINA, which was achieved by modifying pyridyl moieties of the gelator to pyridyl N-oxides. We synthesized two mono-N-oxides (INO and PNO) and a di-N-oxide (diNO) and the gelation studies revealed selective gelation of diNO in water, but the two mono-N-oxides formed crystals. The mechanical strength and thermal stabilities of the gelators were evaluated by rheology and transition temperature (Tgel) experiments, respectively, and the analysis of the gel strength indicated that diNO formed weak gels compared to 4PINA. The SEM image of diNO xerogels showed fibrous microcrystalline networks compared to the efficient fibrous morphology in 4PINA. Single-crystal X-ray analysis of diNO gelator revealed that a hydrogen-bonded dimer interacts with adjacent dimers via C―H∙∙∙O interactions. The non-gelator with similar dimers interacted via C―H∙∙∙N interaction, which indicates the importance of specific non-bonding interactions in the formation of the gel network. The solvated forms of mono-N-oxides support the fact that these compounds prefer crystalline state rather than gelation due to the increased hydrophilic interactions. The reduced gelation ability (minimum gel concentration (MGC)) and thermal strength of diNO may be attributed to the weak intermolecular C―H∙∙∙O interaction compared to the strong and unidirectional N―H∙∙∙N interactions in 4PINA.
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Azyat, Khalid, Darren Makeiff, Bradley Smith, Mickie Wiebe, Steve Launspach, Ashley Wagner, Marianna Kulka i Nicolas Godbert. "The Effect of Branched Alkyl Chain Length on the Properties of Supramolecular Organogels from Mono-N-Alkylated Primary Oxalamides". Gels 9, nr 1 (22.12.2022): 5. http://dx.doi.org/10.3390/gels9010005.
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Mono-N-alkylated primary oxalamide derivatives with different sized branched alkyl tail-groups were excellent low molecular weight gelators for a variety of different organic solvents with different polarities and hydrogen-bonding abilities. Solvent-gelator interactions were analyzed using Hansen solubility parameters, while 1H NMR and FTIR spectroscopy were used to probe the driving forces for the supramolecular gelation. The molecular structures of the twin tail-groups did not significantly affect the supramolecular gelation behavior in different solvents. However, for select solvents, the molecular structures of the tail-groups did have a significant effect on gel properties such as the critical gelator concentration, thermal stability, gel stiffness, gel strength, network morphology, and molecular packing. Finally, metabolic activity studies showed that the primary alkyl oxalamide gelators had no effect on the metabolic activity of mouse immune cells, which suggests that the compounds are not cytotoxic and are suitable for use in biomedical applications.
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Patterson, Anna K., i David K. Smith. "Two-component supramolecular hydrogel for controlled drug release". Chemical Communications 56, nr 75 (2020): 11046–49. http://dx.doi.org/10.1039/d0cc03962d.
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Liu, Shao Zhu, Wei Li Liu, Zhi Gang Liu, Jing Chang Li, Xiao Chun Zhang, Yu Yan Liu i Yong Zhen Wang. "A Phase-Selective Supramolecular Gelator as Oil Solidifier". Applied Mechanics and Materials 457-458 (październik 2013): 284–87. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.284.
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A simple sugar-derived supramolecular gelator of 1,6-dicaprylate sorbitan ester was designed and prepared as new oil solidifier. The gelation tests revealed that the gelator can gel or phase-selectively gel fuel oils, edible oils and some organic solvents. And the SEM images showed the structure of 3D fiber network was formed in the process of gelation. What’s more, the rate of oil removal in water was 85% and the recovery rate of spilled oils reached up to 60.29%.
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Ghosh, Dipankar, Ragnar Bjornsson i Krishna K. Damodaran. "Role of N–Oxide Moieties in Tuning Supramolecular Gel-State Properties". Gels 6, nr 4 (20.11.2020): 41. http://dx.doi.org/10.3390/gels6040041.
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The role of specific interactions in the self-assembly process of low molecular weight gelators (LMWGs) was studied by altering the nonbonding interactions responsible for gel formation via structural modification of the gelator/nongelator. This was achieved by modifying pyridyl moieties of bis(pyridyl) urea-based hydrogelator (4–BPU) and the isomer (3–BPU) to pyridyl N–oxide compounds (L1 and L2, respectively). The modification of the functional groups resulted in the tuning of the gelation properties of the parent gelator, which induced/enhanced the gelation properties. The modified compounds displayed better mechanical and thermal stabilities and the introduction of the N–oxide moieties had a prominent effect on the morphologies of the gel network, which was evident from the scanning electron microscopy (SEM) images. The effect of various interactions due to the introduction of N–oxide moieties in the gel network formation was analyzed by comparing the solid-state interactions of the compounds using single crystal X-ray diffraction and computational studies, which were correlated with the enhanced gelation properties. This study shows the importance of specific nonbonding interactions and the spatial arrangement of the functional groups in the supramolecular gel network formation.
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Alegre-Requena, Juan V., Santiago Grijalvo, Diego Sampedro, Judith Mayr, César Saldías, José Juan Marrero-Tellado, Ramón Eritja, Raquel P. Herrera i David Díaz Díaz. "Sulfonamide as amide isostere for fine-tuning the gelation properties of physical gels". RSC Advances 10, nr 19 (2020): 11481–92. http://dx.doi.org/10.1039/d0ra00943a.
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Saharan, Yajvinder, i Joginder Singh. "Ditetradecyldiphenylmethane- 4,4-dicarbamate supramolecular gelator: Synthesis, characterization and Oil trapping". Research Journal of Chemistry and Environment 26, nr 7 (25.06.2022): 94–100. http://dx.doi.org/10.25303/2607rjce0940100.
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In the present research work, supramolecular organo oil gelator was synthesized using diphenylmethane diisocyanate (DMI) and 1-Tetradecanol for the sorption of oil from oil contaminated soil/water mixture. The prepared gelator was characterized using FTIR, mass spectral techniques and SEM analysis. The FTIR and mass spectra assured the formation of oil gelator. Further, SEM analysis showed porous, fiber-like structures. In mechanism, it was proposed that the organo oil gel leads to self-assembly and further entanglements forming the fibres which finally help in oil uptake/trapping. The maximum uptake of the oil was around 50% initially and it was further increased to 92% using gasoline as the co-congealed solvent. Interestingly, the complete gelation of the oil from oil water emulsion was accomplished inside 20 min of application with good oil recovery. This research work confirmed that the oil removal by organo oil gelator could be employed for treating oil contaminated soil/water mixture.
Rozprawy doktorskie na temat "Supramolecular Gelator"
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Abreu, Marlon de Freitas 1978. "Géis supramoleculares : aspectos químicos e físicos de redes nanofibrilares constituídas por agentes gelificantes baseados em glicosídeos". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249043.
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Orientador: Paulo Cesar Muniz de Lacerda MirandaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: O trabalho versa sobre a síntese de doze gelificantes (LMOGs) e um estudo sobre automontagem supramolecular dos LMOGs na construção de nanofibras. Foram sintetizadas duas séries de compostos derivados do metil 4,6-O-benzilideno-a-D-glicopiranosideo substituído na posição 4 do anel aromático com grupos (G) modificadores de densidade eletrônica, série A (G = n-alcoxil) e série B (G = n-alcoxicarbonil); e dois agentes de reticulação supramolecular (C e D). Fez-se um estudo da supramolecularidade usando várias técnicas. O ensaio de gelificação revelou que os LMOGs da série B enrijecem maior numero de solventes em maior faixa de concentração do que os da série A. A habilidade de gelificação foi destacada nos LMOGs de maior cadeia carbônica. Identificou-se por IV-TF que os LMOGs da série A se agregam por apenas um dos grupos OH, enquanto os LMOGs da série B pelos dois. A MEV mostrou estruturas fibrosas com morfologias cilíndricas e/ou fitas, com o menor diâmetro de 40 nm. Os termogramas no DSC indicaram que a Tgel aumentou com a concentração, porém ela diminuiu com o tamanho da cadeia carbônica em ambas as séries. O UV/vis mostrou que os grupos aromáticos estão arranjados obliquamente e próximos a um empilhamento p. As fibras de ambas as séries apresentaram helicidade P no DC. Observou-se com SAXS que a habilidade de gelificação está relacionada com o crescimento 1D. Os espectros de NOESY confirmam o que foi evidenciado no IV/térmico, sugerindo que as duas séries de LMOGs sofram automontagens diferentes. A mistura de LMOGs e de agente de reticulação não aumentou a habilidade de gelificação nem a estabilidade térmica. Com a técnica de ESI-MS verificou-se que mistura das séries, A + B, leva à agregação randômica. A análise do monocristal permitiu observar o "arranjo 1D", que ajudou a propor com outras técnicas a automontagem dos gelificantes dentro da fibra. Propõe-se que os LMOGs da serie A sofram uma torção angular maior, em relação ao cristal, durante o empacotamento helicoidal do que os LMOGs da serie B, embora as duas apresentem a mesma helicidade (P). Os agentes de reticulação C e D não contribuíram para a ramificação das fibras, mas o D apresentou boa estabilidade térmica e habilidade para enrijecer solventes polares. Por fim, fez-se um breve estudo focando a aplicação em célula solar. Os resultados mostraram que a gelificação pode minimizar a evaporação e o vazamento deste dispositivo, sem afetar muito suas propriedades
Abstract: The work presented in this thesis reports the synthesis of twelve gelators (LMOGs) and the study of the supramolecular self-assembly process in the formation of nanofibers. Two series of 4,6-O-benzylidene-a-D-glucopyranoside derivative compounds with different groups (G) at position 4 of the aromatic ring, series A (G = n-alkoxyl) and B (n-alkoxycarbonyl) and two compounds titled supramolecular crosslinking agents (C e D) were designed to study the effect of substituents (A and B) and effect the mixture of the LMOGs on self-assembly properties. The gelation test revealed that the LMOGs of the series B presented better gelation properties over the wide concentration range than the series A. The presence of long alkyl chains in both series enhanced the ability to gelate various organic solvents. The organogelators were characterized by different techniques. The FT-IR analysis of the gels indicated that the series A undergo a self-assembly process through hydrogen-bonding involving only one of the OH group, while the LMOGs of the series B aggregated with two OH group. Microscopic images (SEM) of the xerogel showed cylindrical or tape-like organized aggregates with small diameters (~40 nm). The DSC studies revealed that the Tgel increases with the molar concentration and decreases with alkyl chain size in both series of the gelators. UV/vis spectroscopy shows that the aromatic groups are obliquely orientated and approximately parallel. The helicity of the fiber of both series found to be P in CD. SAXS studies point that the gelation ability can be related to the uni-dimensional fiber growth. NOESY confirmed the different self-assembly mode between the series A and B observed in FT-IR. Both the gelation ability and Tgel were not increased with the mixtures of LMOGs (A + B or A/B + D). When analyzed in ESI-MS, the mixture of A + B resulted in a random aggregation of LMOGs. X-ray crystallographic analysis allowed creating a model of self-assembly of fiber together with other techniques. Based on these results, was proposed that the fiber of series A undergo a greater torsional deformation than the B, during helical molecular packing when compared to crystal, although the two exhibit the same helicity (P). The compounds C and D behaved not as a crosslinking agents of fiber. However, the compound D acted as gelling agent with high thermal stability in polar solvents. Finally, the gelation test with electrolyte solution revealed that LMOG does not compromise the solar cell performance, showing that the gelation can be applied to avoid the leakage or evaporation of the organic solvent
Doutorado
Quimica Organica
Doutor em Ciências
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Simões, Thiago Augusto 1985. "Reologia de organogéis baseados em glicosídeos aromáticos". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250158.
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Orientador: Edvaldo SabadiniDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Materiais nanoestruturados apresentam-se em muitas formas diferentes. Um grupo de compostos ainda pouco investigado é o grupo dos organogéis, especialmente aqueles cuja estrutura tridimensional de rede é baseada na auto-organização de compostos orgânicos de baixa massa molecular, capazes de promover a gelificação no meio em que se encontram. São os chamados "Low Molecular Organic Gelators ¿ LMOG". Esses materiais termorreversíveis consistem de uma pequena quantidade de LMOG e um líquido orgânico. O presente trabalho visa esclarecer os mecanismos de auto-organização dos LMOG na escala supramolecular. Os LMOG estudados são derivados em moléculas que podem ser divididas em três partes. A parte central é constituída por um anel fenílico. Em uma das partes está ligado um grupo glicosídeo, e em outro ponto do anel uma cadeia alquílica. Procurou-se estudar as características estruturais e cinéticas de géis formados em um solvente aromático (para-xileno) e em um solvente formador de ligações de hidrogênio (n-propanol). Avaliaram-se, então, os efeitos relacionados com o balanço polar-apolar da molécula de LMOG, analisando os géis com 8, 4 e 3 unidades metilênicas da cadeia alquílica, bem como os efeitos de solvatação. A investigação dos fenômenos foi realizada utilizando a reologia rotatória e oscilatória nos regimes diluído e concentrado, aliada às técnicas de microscopia eletrônica de varredura (MEV), difratografia de raios-X e difusão dinâmica da luz (DDL)
Abstract: Nanostructured materials exist in many different ways. A group of compounds which has not been much investigated is the group of organogels, especially those whose three-dimensional network structure is based on the self-assembly of low molecular weight organic compounds. They promote gelation in the medium in which they are. These compounds are titled as "Low Molecular Mass Organic Gelator - LMOG" and they form thermoreversible materials constituted by a small amount of a LMOG and an organic liquid. The work presented in this dissertation aimed to clarify the mechanisms of self-assembly in a supramolecular scale. The LMOG molecules studied have a phenyl ring with a glycoside group bonded in one side and an alkyl chain bonded in the other part of the aromatic ring. The kinetic and structural characteristics of the gel formed in an aromatic solvent (para-xylene) and in a solvent donator of hydrogen bonding (propanol) were investigated. Therefore, the effects emerged from the polar-nonpolar balance of the LMGO molecule with 8, 4 and 4 methyl groups in the alkyl chain, as well as the solvation effect. The investigations were performed using the rotational and oscillatory rheology in dilute and concentrated regimes combined with the techniques of Scanning Electron Microscope (SEM), X-RAY diffraction and Dynamic Light Scattering (DLS)
Mestrado
Físico-Química
Mestre em Química
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Piana, Francesca. "Urea-based supramolecular gelators : molecular structure-gelation relationship and sensing of organophosphorus compounds". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/387350/.
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The aim of this thesis was to study the phenomenon of supramolecular gelation of urea-based gelators and their application as sensors for neutral organophosphorus species such as nerve agents. The work was therefore naturally divided into two major parts. The first part consisted in an investigation of the structure-gelation relationship of a series of urea gelators, in an effort to overcome the serendipitous approach that is widely applied to their discovery. Among the components of the common gelator scaffold that were optimised to deliver the best gelation performance, particular attention was given to the role of the head substituent on its benzene ring. Crystal structure prediction calculations together with liquid- and solid-state NMR were used to understand the molecular reasons behind the observed macroscopic properties of supramolecular gels formed either by nitro- or methoxy-substituted gelators. Remarkably, this approach demonstrated that, rather than electronic effects, it was the nitro substituent’s ability to interfere with the urea hydrogen bond network to cause the differences observed in the gel formation experiments, when compared to the methoxy-analogue. The second part focused on the possible application of bis/tris(urea)-based supramolecular gels as organophosphorus warfare agents’ sensors. After the development of a fast and easily interpretable in-house test, it was possible to observe the effectiveness of different candidates in responding to the presence of either the nerve agent Soman or its simulant dimethyl methyl phosphonate. It was observed that in the presence of the guest molecules gelation could be delayed or even suppressed, suggesting the formation of hydrogen bonds between guest and host that were interfering with the self-assemble of the gelator molecules. Conversely it was also found that, if present in lower amount, dimethyl methyl phosphonate could instead induce a detectable thermo-mechanical reinforcement of the gel network, as confirmed by rheology and calorimetry results, which was ascribed to solvophobic effects.
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Maity, A. "Tailoring the optical properties and morphology of low molecular weight based supramolecular gelators". Thesis(Ph.D.), CSIR- National Chemical Laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4507.
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Foster, Jonathan Andrew. "The design and application of bis-urea derived supramolecular gelators". Thesis, Durham University, 2012. http://etheses.dur.ac.uk/3598/.
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A series of amino-acid derived bis-urea gelators were synthesised, some of which show strong gelation in a wide variety of solvents. The gels were probed at the molecular, microscopic and macroscopic levels to gain insights into the gelation behaviour observed. Mixtures of different gelators also result in gels, some of which show different fibre morphologies and X-ray powder patterns to the pure gelators. The series was extended to include fluorescent 1- and 2-pyrenylalanine derived gelators and the fluorescence behaviour of the gels in solution, the gel state, in mixed gels and with the addition of anions was investigated. Tetrabutylammonium-acetate was found to disrupt urea-hydrogen bonding leading to the break-down of the gels, a process which was followed by NMR spectroscopy, rheometry and fluorescence spectroscopy. Two gelators were used to template the formation of porous polymers which SEM and gas adsorption studies show reflect the different fibre morphologies observed in the gels. The use of supramolecular gels as a medium for controlling the crystallisation of pharmaceutical compounds was developed. Proof of principle for the growth of a wide range of pharmaceutical compounds from a variety of different gels was demonstrated. The supramolecular nature of the gels was exploited by using anions to break down the gels in order to recover the crystals. Comparison of crystals grown from gels with those grown from solution highlighted a number of differences in crystal form, habit and stability. Gelators which mimic the chemical functionality of the drug compound being crystallised were synthesised. A study investigating the crystallisation of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY) showed some differences in polymorphism when crystallised from a gel designed to mimic ROY compared to generic gels. A placement with the particle science group at GSK explored the potential of supramolecular gels for use in early stage screening of pharmaceutical compounds in an industrial setting.
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Zaupa, Alessandro. "Physical crosslinking of gelatin : a supramolecular approach to biomaterials". Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2011/5288/.
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This work describes the realization of physically crosslinked networks based on gelatin by the introduction of functional groups enabling specific supramolecular interactions. Molecular models were developed in order to predict the material properties and permit to establish a knowledge-based approach to material design. The effect of additional supramolecular interactions with hydroxyapaptite was then studied in composite materials.
The calculated properties are compared to experimental results to validate the models. The models are then further used for the study of physically crosslinked networks. Gelatin was functionalized with desaminotyrosine (DAT) and desaminotyrosyl-tyrosine (DATT) side groups, derived from the natural amino acid tyrosine. These group can potentially undergo to π-π and hydrogen bonding interactions also under physiological conditions. Molecular dynamics (MD) simulations were performed on models with 0.8 wt.-% or 25 wt.-% water content, using the second generation forcefield CFF91. The validation of the models was obtained by the comparison with specific experimental data such as, density, peptide conformational angles and X-ray scattering spectra. The models were then used to predict the supramolecular organization of the polymer chain, analyze the formation of physical netpoints and calculate the mechanical properties. An important finding of simulation was that with the increase of aromatic groups also the number of observed physical netpoints increased. The number of relatively stable physical netpoints, on average zero 0 for natural gelatin, increased to 1 and 6 for DAT and DATT functionalized gelatins respectively. A comparison with the Flory-Rehner model suggested reduced equilibrium swelling by factor 6 of the DATT-functionalized materials in water.
The functionalized gelatins could be synthesized by chemoselective coupling of the free carboxylic acid groups of DAT and DATT to the free amino groups of gelatin. At 25 wt.-% water content, the simulated and experimentally determined elastic mechanical properties (e.g. Young Modulus) were both in the order of GPa and were not influenced by the degree of aromatic modification. The experimental equilibrium degree of swelling in water decreased with increasing the number of inserted aromatic functions (from 2800 vol.-% for pure gelatin to 300 vol.-% for the DATT modified gelatin), at the same time, Young’s modulus, elongation at break, and maximum tensile strength increased.
It could be show that the functionalization with DAT and DATT influences the chain organization of gelatin based materials together with a controlled drying condition. Functionalization with DAT and DATT lead to a drastic reduction of helical renaturation, that could be more finely controlled by the applied drying conditions. The properties of the materials could then be influenced by application of two independent methods.
Composite materials of DAT and DATT functionalized gelatins with hydroxyapatite (HAp) show a drastic reduction of swelling degree. In tensile tests and rheological measurements, the composites equilibrated in water had increased Young’s moduli (from 200 kPa up to 2 MPa) and tensile strength (from 57 kPa up to 1.1 MPa) compared to the natural polymer matrix without affecting the elongation at break.
Furthermore, an increased thermal stability from 40 °C to 85 °C of the networks could be demonstrated. The differences of the behaviour of the functionalized gelatins to pure gelatin as matrix suggested an additional stabilizing bond between the incorporated aromatic groups to the hydroxyapatite.Diese Arbeit beschreibt die Entwicklung von durch spezifische physikalische Wechselwirkungen quervernetzten Gelatine-basierten Materialien. Dazu wurden zunächst Computermodelle entwickelt, mit denen Eigenschaften der Materialien vorhergesagt werden sollten, um so eine wissensbasierte Entwicklung zu ermöglichen, um dann die Ergebnisse mit experimentellen Daten zu vergleichen und die Materialien und Modelle als Grundlage für weitere Entwicklungen zu nutzen. Gelatine wurde mit Desaminotyrosin (DAT) und Desaminotyrosyltyrosin (DATT) funktionalisiert, die sich von der natürlichen Aminosäure Tyrosin ableiten. Diese Gruppen können potentiell π-π Wechselwirkungen und Wasserstoffbrückenbindungen auch unter physiologischen Bedingungen eingehen. Es wurden Computersimulationen der Materialien mittels Moleküldynamik durchgeführt, wobei Modelle mit 0.8 Gew.-% und 25 Gew.-% Wassergehalt betrachtet wurden. Die Validierung der Modelle erfolgte durch Vergleich der errechneten mit experimentellen Daten wie z.B. der Dichte, Bindungswinkeln sowie Röntgenstreuungsspektren. Die Modelle wurden dann zur Vorhersage der molekularen Organisation der Polymerketten, Formierung physikalischer Netzpunkte und Berechnung der mechanischen Eigenschaften eingesetzt. Die Funktionalisierung der Gelatine mit DAT bzw. DATT führten wie gewünscht zur Ausbildung physikalischer Netzpunkte durch π-π Wechselwirkungen und Wasserstoffbrücken¬bindungen. Ein Schlüsselergebnis der Simulationen war, dass mit zunehmender Zahl an aromatischen Gruppen auch eine Zunahme der physikalischen Netzpunkte beobachtet werden konnte. Die funktionalisierten Gelatinen konnten durch chemoselektive Reaktion der Aminogruppen der Gelatine mit den freien Carboxylgruppen von DAT und DATT hergestellt werden. Materialien mit 25 Gew.-% Wassergehalt hatten in der Simulation und im Experiment mechanische Eigenschaften derselben Größenordnung (z.B. E-Moduln im unteren GPa-Bereich). Der Quellungsgrad der Materialien im Experiment nahm mit zunehmender Zahl an aromatische Gruppen ab (von 2800 Vol.-% auf 300 Vol.-%), wobei der Elastizitätsmodul, die Bruchdehnung sowie die Zugfestigkeit zunahmen. Die Funktionalisierung der Gelatine ist eine chemische Methode, um die Kettenanordnung auf molekularer Ebene zu beeinflussen, während die genaue Kontrolle der Trocknungs¬bedinguungen von Gelatine-basierten Materialien eine physikalische Methode mit demselben Ziel ist. Es konnte gezeigt werden, dass die Funktionalisierung von Gelatine mit DAT oder DATT zu einer stark verminderten Helixausbildungstendenz, die jedoch durch Variation der Trocknunsgbedingungen noch fein abgestimmt werden konnte. Somit konnten die mechanischen Eigenschaften von Filmen aus funktionlisierter Gelatine mit zwei unabhängigen Methoden eingestellt werden. Komposite der mit DAT oder DATT funktionalisierten Gelatine und Hydroxyapatit (HAp) zeigten deutlich verringerter Quellung. In Zugdehnungsexperimenten und rheologischen Untersuchungen zeigten die Komposite im Gleichgewichtsquellungszustand erhöhte Elastizitätsmoduln (von 200 kPa auf bis zu 2 MPa) und Zugfestigkeit (von 57 kPa auf bis zu 1.1 MPa). Darüber hinaus konnte die Übergangstemperatur Tc deutlich gesteigert werden (von ca. 40 °C auf > 85 °C). Dieses Verhalten ließ sich auf stabilisierende Bindungen zwischen den aromatische Gruppen und dem HAp zurückführen.
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Williams, Kristopher Aaron. "Synthesis and Characterization of Monosaccharide-derived Low Molecular Weight Gelators". ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/135.
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Low molecular weight gelators (LMWGs) are interesting materials whose applications are as diverse and wide ranging as their molecular structures. These materials self-assemble through the formation of non-covelent intermolecular forces and interactions to form supramolecular assemblies that trap solvent within their matrices. Because of the non-covalent nature of the forces of self-assembly, the gelation process is typically thermally reversible. In addition, low molecular weight gelators can also be modified to respond to various stimuli, such as change in pH, presence of enzymes or metal cations, or exposure to light. The design of low molecular weight gelators is often difficult, and most new classes of low molecular weight gelators are discovered by serendipity. As such, it is often useful to use structural templates in the design of LMWGs. Biomolecules, such as steroids, amino acids and peptides, and carbohydrates make excellent templates due to their inherent propensity to self assemble. A review of the current literature regarding the use of biomolecules as templates for the design and synthesis of LMWGs will be presented in chapter 1. Our research group has been active in the research of carbohydrate-based LMWGs for several years, and these results are also briefly reviewed in the related chapters. The synthesis and characterization of ester derivatives of D-galactose, D-glucose, and amide derivatives of D-glucosamine will be discussed in chapters 2-4, along with their evaluation for gelation in aqueous and organic solvents, such as hexane, ethanol, water, and aqueous DMSO or ethanol mixtures.
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Pi, i. Boleda Bernat. "Supramolecular studies on the behaviour of different chiral cycloalkane-based compounds as receptors, gelators and surfactants". Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/400575.
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En aquesta tesi, s’han estudiat quatre diferent sistemes supramoleculars com a receptors, gelificadors o tensioactius. S’ha analitzat la influència de diferents factors estructurals de la molècula senzilla en la seva propietat supramolecular final. S’han utilitzat diferents estratègies per a preparar els compostos estudiats. La combinació de diferents tècniques ens ha permès entendre millor aquests sistemes obtenint un resultat sinèrgic. Els resultats d’aquesta tesi estan dividits en quatre capítols:
1) Diferents receptors d’anions tripodals s’han sintetitzat i la seva complexació amb diferents anions s’ha estudiat. Fent servir RMN, les energies de Gibbs de complexació s’han calculat i la seva afinitat de cordinació s’ha estudiat. Mitjançant càlculs teòrics, l’estructura dels diferents complexes s’ha predit. També, la termodinàmica dels sistemes estudiats s’ha calculat. Els càlculs teòrics ens han permès entendre i racionalitzarels resultats experimentals.
2) Tres famílies diferents de gelificadors basats en carbocicles que contenen dos grups amida s’han estudiat per tal de determinar la influència de la mida de l’anell, les substitucions de l’anell i l’estereoquímica de la molècula en les seves habilitats gelificants. Usant el test de la inversió del tub i racionalitzant-lo amb diferents paràmetres de solubilitat, les habilitats gelificants dels diferents compostos s’han determinat. Aquest estudi s’ha acompanyat amb RMN d’alta resolució. L’agregació s’ha estudiat mitjançant càlculs teòrics, els quals estan en acord amb els espectres de dicroïsme circular obtinguts dels xerogels. Finalment, fent servir SEM, s’ha determinat la morfologia dels agregats.
3) Quatre diferents tensioactius tipus bola s’han sintetitzat i el seu caràcter com a tensioacitus s’ha estudiat per tal de determinar la influència de l’esteroquímica i la regioquímica en el seu comportament com a tensioactius. Fent servir el mètode de la gota penjatn, la variació de la tensió superficial amb la concentració s’ha analitzat. Hem desenvolupat un nou mètode per predir l’estructura dels tensioactius agregats a la superfície. Finalment, les tècniques de cryoTEM i SAXS ens han permès estudiar la morfologia i la mida dels agregats.
4) Al darrer capítol, qutre tensioactius depenents del pH s’han sintetitzat. L’estudi supramolecular de les seves propietats s’ha dut a terme usant diverses tècniques. Aquests tensioactius mostren un interessant comportament àcid-base adequat per a possibles aplicacions biològiques. És per això que s’han estudiat com a possibles nous vectors no-virals per a teràpia gènica fent servir diferents tècniques biofísiques i biològiques. Els resultats mostren que no són tòxics i que tenen propietats interessants per ser usats com a vectors.In this thesis, four different supramolecular systems were studied as receptors, gelators or surfactants. The influence of different structural factors of the single molecule on the final supramolecular properties was analysed. Different strategies were used to prepare the studied compounds. The combination of different techniques leads us to better understand these systems obtaining synergistic results. Results of this thesis are divided in four chapters: 1) Different tripodal anion receptors were synthesised and their complexation with different anions were studied. Using NMR, complexation Gibbs energies were calculated and the binding affinity were studied. Using theoretical calculations, the structure of the complexes were predicted. Also, thermodynamics of the host-guest system were calculated and theoretical calculations lead us to rationalise the experimental results. 2) Three different families of cycloalkane diamide-based gelators were studied to determine the influence of the ring size, the substitutions of the ring and the stereochemistry on the final gelation abilities. Using the tube inversion test and rationalising it with different solubility parameters, the gelation ability was determined. This study was accompanied by high resolution NMR. Self-assembly was studied using theoretical calculations and circular dichroism. Results show that all of the studied gels are chiral despite some of the monomers are meso compounds. Then, using SEM, the morphology of the aggregates was determined. 3) Four different bolaform amphiphiles were synthesised and their behaviour as surfactants were studied to determine the influence of the stereochemistry and the regiochemistry on the final surfactant behaviour. Using the pendant drop method, the variation of the surface tension with the concentration was analysed. We developed a new method to predict the structure of the self-assembled surfactants at the surface. CryoTEM and SAXS were used to determine the morphology and size of the aggregates. 4) In the last chapter, four pH-dependent β-amino acid-based surfactants were synthesised. Supramolecular properties of these systems were studied using pendant drop method, cryoTEM, theoretical calculations, different physicochemical titrations, circular dichroism, UV-vis absorption and DLS. These surfactants show interesting acid-base behaviour suitable for biological applications. They have been studied as potential new non-viral vectors for gene therapy using different biophysical and biological techniques. Results show that these surfactants are not toxic and they have interesting features to be used as vectors.
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Zaupa, Alessandro [Verfasser], i Andreas [Akademischer Betreuer] Lendlein. "Physical crosslinking of gelatin : a supramolecular approach to biomaterials / Alessandro Zaupa. Betreuer: Andreas Lendlein". Potsdam : Universitätsbibliothek der Universität Potsdam, 2010. http://d-nb.info/1014619084/34.
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Pleines, Maximilian. "Viscosity-control and prediction of microemulsions". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS139.
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La viscosité est une propriété fondamentale des fluides complexes et qui reste encore difficile à prédire quantitativement. Cette propriété macroscopique provient de propriétés moléculaires et mésoscopiques. La compréhension et l’estimation de l'évolution de la viscosité avec des paramètres variables est important pour plusieurs applications, entre autres pour l’extraction liquide-liquide et pour la formulation de systèmes tensioactifs aqueux.Dans ce travail, un modèle "minimal" prenant en compte les énergies libres mises en jeu a été développé pour aider à comprendre, contrôler et prédire l'évolution de la viscosité des microémulsions en présence de solutés. Le terme «minimal» signifie dans ce contexte que ce modèle est basé sur un ensemble minimal de paramètres qui sont tous mesurables ou ont une signification physique, ce qui permet d’éviter le recours à des paramètres ajustables. Ce modèle développé dans cette thèse considère les termes chimiques à l'échelle moléculaire, les termes physiques à l'échelle mésoscopique ainsi que les caractéristiques d'écoulement à l'échelle macroscopique a été appliqué sur des microémulsions pauvres en eau utilisé pour l’extraction des métaux ainsi que sur des systèmes tensioactifs anioniques aqueuxViscosity is a fundamental property of complex fluids that is still nowadays extremely difficult to predict quantitatively. This macroscopic property originates from molecular and mesoscopic properties. The understanding and prediction of the evolution of the viscosity with changing parameters is crucial for several applications, amongst others for liquid-liquid extraction processes and for formulation of aqueous surfactant systems.In this work, a “minimal” model taking into account the relevant free energies was developed that helps to understand, control and predict the evolution of the viscosity of microemulsions in presence of solutes. The term “minimal” means in that context that this model is based on a minimal set of parameters that are all measurable and have a physical meaning, thus avoiding input of any adjustable parameter. This model that considers the chemical terms at molecular scale, the physical terms at meso-scale as well as the flow characteristics at macroscale was applied on water-poor extracting microemulsions as well as on aqueous anionic surfactant systems
Książki na temat "Supramolecular Gelator"
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Frédéric, Fages, i Araki K, red. Low molecular mass gelators: Design, self-assembly, function. Berlin: Springer, 2005.
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Frederic, Fages, i Araki K, red. Low molecular mass gelators: Design, self-assembly, function. Berlin: Springer, 2005.
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Fages, Frederic. Low Molecular Mass Gelators: Design, Self-Assembly, Function. Springer Berlin / Heidelberg, 2010.
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Fages, Frederic. Low Molecular Mass Gelators : Design, Self-Assembly, Function (Topics in Current Chemistry) (Topics in Current Chemistry). Springer, 2005.
Znajdź pełny tekst źródłaCzęści książek na temat "Supramolecular Gelator"
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Rubio-Magnieto, Jenifer, i Beatriu Escuder. "Chapter 5. Exploring Gelator Efficiency". W Monographs in Supramolecular Chemistry, 129–66. Cambridge: Royal Society of Chemistry, 2018. http://dx.doi.org/10.1039/9781788013147-00129.
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Dastidar, Parthasarathi, Uttam Kumar Das, Tapas Kumar Adalder, Joydeb Majumder i Rajdip Roy. "Designing Charge-Assisted Hydrogen Bonded Supramolecular Gelators". W Lecture Notes in Chemistry, 101–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-45780-1_4.
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Esch, Jan, Franck Schoonbeek, Maaike Loos, E. Marc Veen, Richard M. Kellogg i Ben L. Feringa. "Low Molecular Weight Gelators for Organic Solvents". W Supramolecular Science: Where It Is and Where It Is Going, 233–59. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4554-1_14.
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Loh, X. J. "Supramolecular Gelators in a Biomedical Context". W Comprehensive Supramolecular Chemistry II, 213–25. Elsevier, 2017. http://dx.doi.org/10.1016/b978-0-12-409547-2.12567-3.
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Bhattacharya, Santanu. "Design of amphiphiles for the modulation of catalytic, membranous and gelation properties". W Supramolecular Organization and Materials Design, 146–71. Cambridge University Press, 2001. http://dx.doi.org/10.1017/cbo9780511564987.006.
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Yegin, Cengiz, Cenk Temizel, Yagmur Yegin, Zinyat Agharzayeva, Mufrettin Murat Sari, Bao Jia i Askar Urakov. "Improving Reservoir Conformance Control Through Next-Generation Supramolecular Gelators and Their Use in Hydraulic Fracturing". W SPE Annual Caspian Technical Conference and Exhibition. Society of Petroleum Engineers, 2017. http://dx.doi.org/10.2118/188997-ms.
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Yegin, Cengiz, Cenk Temizel, Yagmur Yegin, Zinyat Agharzayeva, Mufrettin Murat Sari, Bao Jia i Askar Urakov. "Improving Reservoir Conformance Control Through Next-Generation Supramolecular Gelators and their Use in Hydraulic Fracturing (Azeri)". W SPE Annual Caspian Technical Conference and Exhibition. Society of Petroleum Engineers, 2017. http://dx.doi.org/10.2118/188997-az.
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Almeida, Ekmagage Don N., Leela Rakesh, Stanley Hirschi i Anja Mueller. "Solution Rheology of Saline and Polysaccharide Systems". W ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15906.
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The problem of the characterization of the solution properties of water soluble polymers is long-standing. These polymers tend to form aggregated supramolecular gels that are resistant to molecular dispersion. These materials are being widely used in a variety of industrial applications. Their principle functions are as rheological modifiers, where they thicken or gel solutions in products such as hair-care, detergents, air fresheners and foods; as flocculants for particle separation as applied to water clarification, sewage, and effluent treatment, and as stabilizers to control the properties of concentrated suspension and emulsions, for example in paints, pesticides, dyes, and pharmaceutical industries. Therefore it is important to understand their rheological properties under various operating conditions such as stress, strain, temperature etc, which will induce gelation. The rheological properties of starch gels of high concentration (up to 86% starch) have been investigated before [1]. In this paper we have investigated experimentally the shear viscosity and viscoelasticity properties of saline and polysaccharide suspensions at various low concentrations and pH at different temperatures using controlled stress and strain rheometers (Vilastic-3 and AR 2000). The data were then fitted with the power law and Cross model for low and higher concentrations respectively. The present results show that the viscosity/elasticity does not significantly change for low concentrations at different pH values. The maximum viscosity/elasticity was obtained around pH 5-7.4 at higher concentrations.