Surface‐enhanced Raman scattering on colloid gels originated from low molecular weight gelator

Miljanić, Snežana; Frkanec, Leo; Biljan, Tomislav; Meić, Zlatko; Žinić, Mladen

doi:10.1002/jrs.2039

Cited by 12 publications

(13 citation statements)

References 33 publications

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“…The experiments are carried out in 10-mM Tris-HCl pH 8 + 1-mM EDTA buffer with the addition of 20-mM NaCl. The density of the solution is matched to that of polystyrene (1.05 g/cm 3 ) by adding sucrose. To avoid nonspecific attraction we add free biotin to the solution.…”

Section: Methodsmentioning

confidence: 99%

“…The latter have great technological importance. Colloidal gels find applications in synthetic colloid porous materials (1,2), functionalization of surfaces and films production (3,4), ceramics processing (5,6), protein assemblies (7,8), food science (9,10), and soft matter (11,12). Although they have been known for some time (13,14), it has only recently been understood that the colloidal gels arise as a result of arrested phase separation (15)(16)(17)(18).…”

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confidence: 99%

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Arrested demixing opens route to bigels

Varrato

Michele

Belushkin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

107

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Understanding and, ultimately, controlling the properties of amorphous materials is one of the key goals of material science. Among the different amorphous structures, a very important role is played by colloidal gels. It has been only recently understood that colloidal gels are the result of the interplay between phase separation and arrest. When short-ranged attractive colloids are quenched into the phase-separating region, density fluctuations are arrested and this results in ramified amorphous space-spanning structures that are capable of sustaining mechanical stress. We present a mechanism of aggregation through arrested demixing in binary colloidal mixtures, which leads to the formation of a yet unexplored class of materials--bigels. This material is obtained by tuning interspecies interactions. Using a computer model, we investigate the phase behavior and the structural properties of these bigels. We show the topological similarities and the geometrical differences between these binary, interpenetrating, arrested structures and their well-known monodisperse counterparts, colloidal gels. Our findings are supported by confocal microscopy experiments performed on mixtures of DNA-coated colloids. The mechanism of bigel formation is a generalization of arrested phase separation and is therefore universal.spinodal decomposition | DNA-coated colloids | programmable interactions | amorphous self-assembly T he properties of a self-assembled material are ultimately controlled by the interactions among its building blocks and by the conditions in which they are prepared. It is by tuning these two properties that different structures can be obtained. Shortranged attractive colloidal systems, for example, can form crystals, two glasses of different origin, or gels. The latter have great technological importance. Colloidal gels find applications in synthetic colloid porous materials (1, 2), functionalization of surfaces and films production (3, 4), ceramics processing (5, 6), protein assemblies (7, 8), food science (9, 10), and soft matter (11, 12). Although they have been known for some time (13,14), it has only recently been understood that the colloidal gels arise as a result of arrested phase separation (15-18).The gels are characterized by a ramified amorphous spacespanning structure that is capable of sustaining mechanical stress. The colloidal density plays a crucial role in the aggregation and therefore in the resulting structure. At low densities, irreversible aggregation leads to fractal gels. At intermediate densities more compact porous structures are observed, whereas a homogeneous glass emerges when the solute occupies more than 50% of the volume (11,10,14,19).It has been proven that when colloidal particles are quenched into the gas-liquid phase separation region, gelation occurs as a consequence of dynamic arrest that interferes with phase separation (15, 18). After the quench, the system is thermodynamically unstable and strong density fluctuations set in, favoring the separation of the fluid into two ...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Arrested demixing opens route to bigels

Varrato

Michele

Belushkin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

107

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“…The active vibrations in IR cause a change in the dipole moment. Vibrations of bonds or a group of bonds include stretching, bending, scissoring, rocking and twisting [11][12][13][14]. The analysis of intensities or shifts of wavenumbers can probe involvement of specific bonds in gel network building.…”

Section: Ir Spectroscopymentioning

confidence: 99%

“…The hydrogen bonding involving, for example, the carbonyl or amide groups, which often contribute to the building of hydrogel network, is frequently hidden by the water hydrogen bonding. In such cases, the replacement of water with deuterated water is required [13,14].…”

Section: Ir Spectroscopymentioning

confidence: 99%

Characterization and Tailoring the Properties of Hydrogels Using Spectroscopic Methods

Ioniţă¹

2016

Emerging Concepts in Analysis and Applications of Hydrogels

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Hydrogels represent heterogeneous systems that consist of a large amount of water retained by a three-dimensional network. The hydrogel network is the result of assembly through physical interactions or chemical cross-linking of polymers or small molecules. The applications of hydrogels (water purification, tissue regeneration, therapeutic delivery, bio-detection or bio-imaging, etc.) depend on their physicochemical properties and structural features. Although electron microscopy and viscoelastic measurements provide general information about a gel material, the spectroscopic methods complement these methods and also afford a deep insight into the gel structure. In this chapter, the applications of several spectroscopic methods for characterizing polymeric or supramolecular hydrogels are discussed. Thus, this review highlights the particular application of vibrational spectroscopy, circular dichroism, fluorescence (these providing information on assembly in the network), interactions that occur between network and solvent (water), pulsed-field gradient NMR (determination of mesh size) and EPR spectroscopy (a method that can provide extensive information regarding the assembly process, diffusion and release).

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“…The advances in syntesis have allowed the fabrication of colloidal particles in a variety of sizes, shapes and functionality [6][7][8] , contributing to the increasing interest in the field. Colloidal gels have been used for a wide range of applications such as synthetic colloid porous materials 9,10 , functionalisation of surfaces and films production 11,12 , ceramics processing 13,14 , foams 15 , protein systems 16,17 , food science 1, 18 , soft matter 6,19 and bio-engineering 20 . One common route to colloidal gelation is through arrested phase separation 5,[21][22][23][24][25][26] .…”

Section: Introductionmentioning

confidence: 99%

Multi-component colloidal gels: interplay between structure and mechanical properties

et al. 2020

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We present a detailed numerical study of multi-component colloidal gels interacting sterically and obtained by arrested phase separation. Under deformation, we found that the interplay between the different intertwined networks is key. Increasing the number of component leads to softer solids that can accomodate progressively larger strain before yielding. The simulations highlight how this is the direct consequence of the purely repulsive interactions between the different components, which end up enhancing the linear response of the material. Our work provides new insight into mechanisms at play for controlling the material properties and open the road to new design principles for soft composite solids 0 a

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Surface‐enhanced Raman scattering on colloid gels originated from low molecular weight gelator

Cited by 12 publications

References 33 publications

Arrested demixing opens route to bigels

Arrested demixing opens route to bigels

Characterization and Tailoring the Properties of Hydrogels Using Spectroscopic Methods

Multi-component colloidal gels: interplay between structure and mechanical properties

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