In-Situ Observation of Drying Process of a Latex Droplet by Synchrotron Small-Angle X-ray Scattering

Hu, Shanshan; Rieger, Jens; Lai, Yuqing; Roth, Stephan V.; Gehrke, Rainer; Men, Yongfeng

doi:10.1021/ma800451n

Cited by 30 publications

(39 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1) 27 . Vertical SAXS enables the direct observation of the structural development of NP dispersion during drying without any gravity-related restrictions, which conventional (horizontal) synchrotron beams cannot achieve [18][19][20][21][22][23][24][25] . We use aqueous dispersion of nano-silica and poly(vinyl alcohol)…”

Section: Introductionmentioning

confidence: 99%

Structural Development of Nanoparticle Dispersion during Drying in Polymer Nanocomposite Films

Kim

Hyun

Struth³

et al. 2016

Macromolecules

View full text Add to dashboard Cite

Dispersions of nanoparticles (NPs) in a polymer matrix are a key element to set various properties of solution-cast polymer nanocomposite films. While the dispersion state of NPs in nanocomposite films has been extensively studied over the last decades, the structural development during drying and the relation of liquid and solid structure still remains poorly understood. In the present work, we study how NP dispersions develop during drying in polymer nanocomposite films, particularly focusing on the role of particle-polymer interaction in the structural development. Aqueous dispersions of nano-silica and poly(vinyl alcohol) are used as a model NP/polymer mixtures, where the particle-polymer interaction can systemically be varied via the pH. A novel vertical small angle X-ray scattering technique enables us to directly observe the development of NPs dispersion during drying. At a high pH 10, where silica particles have a poor affinity to PVA, SAXS intensity evolution shows phase separation during drying, resulting in the formation of dense aggregates of bare particles in the solid film. On the other hand, at a low pH 3, where silica particles have a good affinity with PVA, the SAXS data indicates a gradual densification of the NPs while maintaining a constant inter-particle distance, which is originating from adsorbed PVA. The resulting solid film after drying exhibits an improved dispersion of NPs. The evaluation of the inter-particle interaction suggests that the adsorbed polymer plays generally a key role in the uniform distribution of NPs in solid films, as it sterically stabilizes NPs over short ranges during all drying stages whereas depletion attraction dominates at longer ranges.

show abstract

Section: Introductionmentioning

confidence: 99%

Structural Development of Nanoparticle Dispersion during Drying in Polymer Nanocomposite Films

Kim

Hyun

Struth³

et al. 2016

Macromolecules

View full text Add to dashboard Cite

show abstract

“…A particularly interesting system is based on latex film formation. The process of formation of pure latex films has attracted considerable attention over the past two decades [36][37][38][39][40][41][42][43][44] . Latex beads are brought into contact by evaporation of the aqueous solvent above the minimal film formation temperature.…”

Section: Introductionmentioning

confidence: 99%

Modeling of Intermediate Structures and Chain Conformation in Silica–Latex Nanocomposites Observed by SANS During Annealing

et al. 2012

View full text Add to dashboard Cite

Abstract:The evolution of the polymer structure during nanocomposite formation and annealing of silica-latex nanocomposites is studied using contrast-variation small angle neutron scattering.The experimental system is made of silica nanoparticles (R si ≈ 8 nm) and a mixture of purpose-synthesized hydrogenated and deuterated nanolatex (R latex ≈ 12.5 nm). The progressive disappearance of the latex beads by chain interdiffusion and release in the nanocomposites is analyzed quantitatively with a model for the scattered intensity of hairy latex beads and an RPA description of the free chains. In silica-free matrices and nanocomposites of low silica content (7%v), the annealing procedure over weeks at up to T g + 85 K results in a molecular dispersion of chains, the radius of gyration of which is reported.At higher silica content (20%v), chain interdiffusion seems to be slowed down on time-scales of weeks, reaching a molecular dispersion only at the strongest annealing. Chain radii of gyration are found to be unaffected by the presence of the silica filler. Tables: 5 2 Figures: 7

show abstract

“…Expectedly, the obtained large-area crack-free PNIPAm-poly (St-MMA-AA) composite opal PCs show a single-crystalline property determined by GISAXS, which is a nondestructive tool to characterize the macroscopic single crystal structure of PCs. [30][31][32][33] Figure 2 ( Supplementary Figures S3a, b) presents the GISAXS result of the as-prepared large-area crack-free PCs. The incident beam was parallel to the (111) plane, and thus the collected data were from o1104 or o11 24 zones.…”

Section: Results and Discussion Characterization Of Large-area Crackmentioning

confidence: 99%

Large-area crack-free single-crystal photonic crystals via combined effects of polymerization-assisted assembly and flexible substrate

et al. 2012

View full text Add to dashboard Cite

Cracking of photonic crystals (PCs) has received considerable attention because of its severe limitation to PC's applications in high-performance optics devices. Although enormous efforts have been focused on the understanding and elimination of the uncontrolled cracks in the self-assembly process, no reliable, low cost and scalable methods have been demonstrated for the fabrication of large (cm or more) crack-free single-crystalline PCs. Herein, we present a facile, reliable approach for the assembly of crack-free single-crystalline PCs on the centimeter scale by the synergistic effects of substrate deformation and monomer infiltration/polymerization. The co-assembling monomer infiltrates and polymerizes in the interstices of the colloidal spheres to form an elastic polymer network, which could lower the tensile stress generated from colloid shrinkage and strengthen the long-range interactions of the colloidal spheres. Otherwise, the timely transformation of the flexible substrate releases the residual stress. This facile, scalable and environment-friendly approach to centimeter-scale crack-free singlecrystalline PCs will not only prompt the practical applications of PCs in high-performance optics devices, but also have great implications for the fabrication of crack-free thin films in other fields, such as wet clays, coating and the ceramic industry.Scheme 1 Fabrication process for crack-free photonic crystals (PCs) by polymerization-assisted assembly on aluminium foil. In the assembly process, the monomer polymerizes and forms an elastic polymer in the interstices of the colloidal spheres. The elastic deformation of the as-formed polymer counteracts the volume change resulted from latex shrinkage and decreases the tensile stress generated. Meanwhile, the substrate deformation releases the residual stress. Both contribute to the achievement of crack-free single-crystalline PCs. Polymerization-assisted assembly and flexible substrate J Zhou et al Figure 1 Scanning electronic microscopy images, ultraviolet-vis spectra of the crack-free PNIPAm/colloid composite opal (a-c) and poly N-isopropyl acrylamide inverse opal (d-f) photonic crystals (PCs) assembled on Al foils. The inset in (a) is a digital photograph of crack-free PC taken at an angle of ca 451 from the sample surface, and the scale bar is 1 cm. The inset in (b) is the magnified SEM image. These SEM images indicate that cracks have been completely eliminated from the PCs. Narrower full-width-at-half-maximum is observed for the crack-free colloidal PCs compared with that of cracked PCs. Polymerization-assisted assembly and flexible substrate J Zhou et al This work is licensed under the Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 Unported License. To view a copy of this license, visit http:// creativecommons.org/licenses/by-nc-nd/3.0/ Supplementary Information accompanies the paper on the NPG Asia Materials website (http://www.nature.com/am) Polymerization-assisted assembly and flexible substrate J Zhou et al

show abstract

In-Situ Observation of Drying Process of a Latex Droplet by Synchrotron Small-Angle X-ray Scattering

Cited by 30 publications

References 37 publications

Structural Development of Nanoparticle Dispersion during Drying in Polymer Nanocomposite Films

Structural Development of Nanoparticle Dispersion during Drying in Polymer Nanocomposite Films

Modeling of Intermediate Structures and Chain Conformation in Silica–Latex Nanocomposites Observed by SANS During Annealing

Large-area crack-free single-crystal photonic crystals via combined effects of polymerization-assisted assembly and flexible substrate

Contact Info

Product

Resources

About