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Orlando J. Rojas - One of the best experts on this subject based on the ideXlab platform.

  • Particulate Coatings via Evaporation-Induced Self-Assembly of Polydisperse Colloidal Lignin on Solid Interfaces
    Langmuir, 2018
    Co-Authors: Oriol Cusola, Piotr Batys, Samu Kivistö, Blaise L. Tardy, Luiz G. Greca, Sampsa Vierros, Maria Sammalkorpi, M. Blanca Roncero, Orlando J. Rojas
    Abstract:

    Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via Evaporation-Induced Self-Assembly. The stratification of the particles at the solid–air interface was markedly influenced, but not monotonically, by the drying rate. Cross-sectional imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using particles with a mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, interparticle forces, and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano- and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.

  • Particulate Coatings via Evaporation-Induced Self-Assembly of Polydisperse Colloidal Lignin on Solid Interfaces
    Langmuir, 2018
    Co-Authors: Oriol Cusola, Piotr Batys, Mariko Ago, Samu Kivistö, Blaise L. Tardy, Luiz G. Greca, Sampsa Vierros, Maria Sammalkorpi, M. Blanca Roncero, Orlando J. Rojas
    Abstract:

    Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via Evaporation-Induced Self-Assembly (EISA). The stratification of the particles at the solid-air interface was markedly influenced but not monotonically, by the drying rate. Cross section imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using mineral particles with mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, inter-particle forces and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.

Oriol Cusola - One of the best experts on this subject based on the ideXlab platform.

  • Particulate Coatings via Evaporation-Induced Self-Assembly of Polydisperse Colloidal Lignin on Solid Interfaces
    Langmuir, 2018
    Co-Authors: Oriol Cusola, Piotr Batys, Samu Kivistö, Blaise L. Tardy, Luiz G. Greca, Sampsa Vierros, Maria Sammalkorpi, M. Blanca Roncero, Orlando J. Rojas
    Abstract:

    Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via Evaporation-Induced Self-Assembly. The stratification of the particles at the solid–air interface was markedly influenced, but not monotonically, by the drying rate. Cross-sectional imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using particles with a mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, interparticle forces, and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano- and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.

  • Particulate Coatings via Evaporation-Induced Self-Assembly of Polydisperse Colloidal Lignin on Solid Interfaces
    Langmuir, 2018
    Co-Authors: Oriol Cusola, Piotr Batys, Mariko Ago, Samu Kivistö, Blaise L. Tardy, Luiz G. Greca, Sampsa Vierros, Maria Sammalkorpi, M. Blanca Roncero, Orlando J. Rojas
    Abstract:

    Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via Evaporation-Induced Self-Assembly (EISA). The stratification of the particles at the solid-air interface was markedly influenced but not monotonically, by the drying rate. Cross section imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using mineral particles with mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, inter-particle forces and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.

Jitendra Bahadur - One of the best experts on this subject based on the ideXlab platform.

  • Formation of hollow spherical and doughnut microcapsules by Evaporation Induced Self-Assembly of nanoparticles: effects of particle size and polydispersity
    Soft Matter, 2012
    Co-Authors: Jitendra Bahadur, S. Mazumder, Shovit Bhattacharya
    Abstract:

    Understanding the role of various physicochemical parameters is essential in order to control the microstructure during Evaporation Induced Self-Assembly in drying colloidal droplets. In the present work, the effect of particle size and its distribution on formation of spherical and doughnut shaped hollow microcapsules during rapid Evaporation Induced Self-Assembly of colloidal droplets has been elucidated. It has been demonstrated that hollow spherical microcapsules with substantial shell thickness are formed for small size and low polydispersity of the nanoparticles in a virgin dispersion. A few of such microcapsules, even with relatively significant shell thickness, burst in order to equilibrate force balance during drying. In contrast, when the size and polydispersity are relatively high, a morphological transformation occurs and the drying droplets release the strain through formation of doughnut shaped grains. Two levels of structural hierarchy and ageing effects of the assembled microcapsules are investigated using small-angle neutron/X-ray scattering and scanning electron microscopy.

  • One-step fabrication of thermally stable TiO2/SiO2 nanocomposite microspheres by Evaporation-Induced Self-Assembly.
    Langmuir, 2012
    Co-Authors: Jitendra Bahadur, S. Mazumder, P.u. Sastry, Bhaskar Paul, Himal Bhatt, S. G. Singh
    Abstract:

    The Evaporation-Induced Self-Assembly of mixed colloids has been employed to synthesize microspheres of TiO2/SiO2 nanocomposites. Small-angle neutron/X-ray scattering and scanning electron microscopy experiments reveal the hierarchical morphology of the microspheres. Although the internal structure of the microspheres, consisting of solely silica nanoparticles, gets significantly modified with time because of the reduction in the high specific surface area by internal coalescence, the same for the composite microspheres remains stable over an aging time of 1 year. Such temporal stability of the composite microspheres is attributed to the inhibition of coalescence of the silica nanoparticles in the presence of titania nanoparticles. X-ray diffraction and thermogravimetric results show the improved thermal stability of the composite grains against the anatase-to-rutile phase transition. Such thermal stability is attributed to the suppression of the growth of titania nanoparticles in the presence of silica n...

  • Evaporation Induced Self-Assembly of nanoparticles in realizing hollow microcapsules
    2012
    Co-Authors: Jitendra Bahadur, S. Mazumder
    Abstract:

    Hollow spherical microcapsules are realized using Evaporation Induced self assembly of silica nanoparticles by spray drying method. Nanoparticles in spray droplets get jammed, during water Evaporation, in an anisotropic fashion, at droplet air-water interface by the action of attractive capillary force. Two levels of structural hierarchy of the microcapsules are investigated using small-angle neutron scattering and scanning electron microscopy.

  • Nanocomposite silica surfactant microcapsules by Evaporation Induced self assembly: tuning the morphological buckling by modifying viscosity and surface charge
    Soft Matter, 2012
    Co-Authors: Jitendra Bahadur, Shovit Bhattacharya, S. Mazumder, Gunjan Verma, Puthusserickal A. Hassan, K. Vijai, Pankaj Doshi
    Abstract:

    Nanocomposite microcapsules of silica and surfactants have been synthesized using Evaporation Induced Self-Assembly through spray drying. It was established using electron microscopy and small-angle neutron/X-ray scattering experiments that the viscosity of the virgin dispersion and surface charge of colloidal components play a significant role in the buckling of spray droplets during drying. Hollow spherical grains are realized at relatively low viscosity and higher surface charge while mushroom like grains manifest at higher viscosity and lower surface charge. In the intermediate conditions, deformed doughnut shaped microcapsules are obtained. Scattering experiments establish the presence of the organization of micelle like aggregates of surfactants in the dried grains and also corroborate with the observations from electron microscopy. A plausible mechanism regarding the chronological pathways of morphological transformation is illustrated. Computer simulation, based on buckling of an elastic shell using a surface evolver, has been attempted in order to corroborate the experimental results.

  • Arrest of morphological transformation during Evaporation-Induced Self-Assembly of mixed colloids in micrometric droplets by charge tuning
    Soft Matter, 2011
    Co-Authors: Jose Savio Melo, Jitendra Bahadur, S. Mazumder, Shovit Bhattacharya, Stanislaus F. D'souza, Henrich Frielinghaus, Günter Goerigk, Rudolf Loidl
    Abstract:

    Self-assembled grains of mixed colloids have been synthesized using Evaporation Induced Self-Assembly (EISA) by spray drying. We demonstrate using electron microscopy and small-angle neutron scattering experiments that buckling driven sphere to deformed-doughnut like morphological transformation in such a process can be arrested by proper tuning of the surface charge on the colloidal components. The buckling amplitude diminishes with a reduction in stabilization force between the colloidal particles. It is established that such arrest of morphological transformation is related to an effective exposure of the surface of softer component at gas–liquid interface. Scattering experiments confirm relatively more compact structure of the non-buckled grains compared to that of the buckled grains. A plausible mechanism regarding the arrest of morphological transformation by surface charge tuning is illustrated.

Sara Bals - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of aluminum containing hierarchical mesoporous materials with columnar mesopore ordering by Evaporation Induced self assembly
    Microporous and Mesoporous Materials, 2016
    Co-Authors: Mert Kurttepeli, Roel Locus, Danny Verboekend, Filip De Clippel, Eric Breynaert, Johan A Martens, Bert F Sels, Sara Bals
    Abstract:

    Abstract The incorporation of aluminum into the silica columns of hierarchical mesoporous materials (HMMs) was studied. The HMMs were synthesized by a combination of hard and soft templating methods, forming mesoporous SBA-15-type silica columns inside the pores of anodic aluminum oxide membranes via Evaporation Induced Self-Assembly (EISA). By adding Al-isopropoxide to the EISA-mixture a full tetrahedral incorporation of Al and thus the creation of acid sites was achieved, which was proved by nuclear magnetic resonance spectroscopy. Electron microscopy showed that the use of Al-isopropoxide as an Al source for the HMMs led to a change in the mesopore ordering of silica material from circular hexagonal (donut-like) to columnar hexagonal and a 37% increase in specific surface (BET surface). These results were confirmed by a combination of nitrogen physisorption and small-angle X-ray scattering experiments and can be attributed to a swelling of the P123 micelles with isopropanol. The columnar mesopore ordering of silica is advantageous towards the pore accessibility and therefore preferential for many possible applications including catalysis and adsorption on the acid tetrahedral Al-sites.

Piotr Batys - One of the best experts on this subject based on the ideXlab platform.

  • Particulate Coatings via Evaporation-Induced Self-Assembly of Polydisperse Colloidal Lignin on Solid Interfaces
    Langmuir, 2018
    Co-Authors: Oriol Cusola, Piotr Batys, Samu Kivistö, Blaise L. Tardy, Luiz G. Greca, Sampsa Vierros, Maria Sammalkorpi, M. Blanca Roncero, Orlando J. Rojas
    Abstract:

    Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via Evaporation-Induced Self-Assembly. The stratification of the particles at the solid–air interface was markedly influenced, but not monotonically, by the drying rate. Cross-sectional imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using particles with a mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, interparticle forces, and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano- and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.

  • Particulate Coatings via Evaporation-Induced Self-Assembly of Polydisperse Colloidal Lignin on Solid Interfaces
    Langmuir, 2018
    Co-Authors: Oriol Cusola, Piotr Batys, Mariko Ago, Samu Kivistö, Blaise L. Tardy, Luiz G. Greca, Sampsa Vierros, Maria Sammalkorpi, M. Blanca Roncero, Orlando J. Rojas
    Abstract:

    Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via Evaporation-Induced Self-Assembly (EISA). The stratification of the particles at the solid-air interface was markedly influenced but not monotonically, by the drying rate. Cross section imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using mineral particles with mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, inter-particle forces and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.