Aerosol Process for the<i>In Situ</i>Coating of Nanoparticles with a Polymer Shell

Poostforooshan, Jalal; Rennecke, S.; Gensch, Manuel; Beuermann, Sabine; Brunotte, Gabriella-Paula; Ziegmann, Gerhard; Weber, Alfred P.

doi:10.1080/02786826.2014.964354

Cited by 17 publications

(10 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For a TEOS concentration of 0.7 ppmv the thickness of the liquid coating measured before collection increases with time corroborating Equation (1). An induction period is reported here before condensation linearly increases with time, as for the condensation of organic vapors on metal nanoparticles [ 29 ]. The solid coating also increases with time.…”

Section: Resultsmentioning

confidence: 99%

“…While spherical nanoparticles facilitate the investigation of the coating kinetics (“idealized system”), nanoparticles in technical applications are mostly encountered as agglomerates consisting of much smaller primary particles as shown in Figure 2 (left). The concave surface areas in the necks between individual primary particles as well as in the interior of the highly ramified agglomerates are most prone for condensational effects inducing capillary condensation [ 29 ]. Therefore, the coating of nanoparticle agglomerates is a superposition of structure-induced deposition and reaction to form SiO x layers.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, another surface sensitive in situ technique is used here to follow the degree of surface coverage, i.e. , the aerosol photoemission (APE) [ 29 ]. Since SiO 2 has a high photothreshold (>10 eV [ 30 ]) that can only be overcome by extreme short wavelength UV light (far below UV-C), silica coatings are commonly employed to inhibit photocatalytic effects of sun blocking nanoparticles such as ZnO or TiO 2 [ 1 ] by suppressing the exchange of photogenerated species with the environment [ 2 ].…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Post-Plasma SiOx Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications

et al. 2016

View full text Add to dashboard Cite

The plasma-based aerosol process developed for the direct coating of particles in gases with silicon oxide in a continuous chemical vapor deposition (CVD) process is presented. It is shown that non-thermal plasma filaments induced in a dielectric barrier discharge (DBD) at atmospheric pressure trigger post-DBD gas phase reactions. DBD operating conditions are first scanned to produce ozone and dinitrogen pentoxide. In the selected conditions, these plasma species react with gaseous tetraethyl orthosilicate (TEOS) precursor downstream of the DBD. The gaseous intermediates then condense on the surface of nanoparticles and self-reactions lead to homogeneous solid SiOx coatings, with thickness from nanometer to micrometer. This confirms the interest of post-DBD injection of the organo-silicon precursor to achieve stable production of actives species with subsequent controlled thickness of SiOx coatings. SiOx coatings of spherical and agglomerated metal and metal oxide nanoparticles (Pt, CuO, TiO2) are achieved. In the selected DBD operating conditions, the thickness of homogeneous nanometer sized coatings of spherical nanoparticles depends on the reaction duration and on the precursor concentration. For agglomerates, operating conditions can be tuned to cover preferentially the interparticle contact zones between primary particles, shifting the sintering of platinum agglomerates to much higher temperatures than the usual sintering temperature. Potential applications for enhanced thermal stability and tunable photoactivity of coated agglomerates are presented.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Post-Plasma SiOx Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications

et al. 2016

View full text Add to dashboard Cite

show abstract

“…[ 30 ] On the other hand, not all initiators need activation, as was the case with glycidyl methacrylate on Ag and SiO 2 nanoparticles aerosol. [ 145 ] NH 3 initiated the anionic polymerization involving epoxide ring‐opening. Although their initiation was delayed, the deposition results appeared rather conformal.…”

Section: Processes: Initiation Reagents and Substratesmentioning

confidence: 99%

Condensation‐Controlled Toposelective Vapor Deposition in Nano‐ and Microcavities: Theory, Methods, Applications, and Related Technologies

Lovikka¹

2022

Adv Materials Inter

View full text Add to dashboard Cite

fabricable while we are facing increasing complexity in, for example, microelectronics. [6,7] For these reasons, challenges such as bad pattern alignment, [8,9] or pinch-off of pores and void formation [10][11][12][13] in top-down fabrication need to be addressed. On the other hand, a continuous film causes tradeoffs in desirable properties in many nanotechnological applications, such as losing mesoporosity while increasing the mechanical properties of an aerogel [14] or reducing catalytic activity while increasing catalyst stability against sintering. [15] To counter these problems, even atomic layer deposition (ALD), a method known for its superior conformality, has been expanded into area-selective fabrication by the addition of etching and functionalization steps in the workflow. [16][17][18][19] However, additional steps make the workflow increasingly slow, complex, and dependent on surface chemistries. There is also a growing interest in area-selectivity based on properties of precursors and substrates in ALD, [20] but new requirements on precursors would narrow down potential reagents. Furthermore, even conformal methods would leave voids inside ink-bottle-shaped pores and under composite undercuts [21] because conformal methods would clog the pore mouths before filling the internal parts. These problems have very recently revoked calls for profound changes and even a paradigm shift toward selective functionalization in the nanoscale. [18,20,[22][23][24][25] Special attention should be paid to inherently non-conformal methods, especially if they are surface-selective towards cavities. This includes both surface-selective subconformal coatings, those that coat only extremities and protrusions of a substrate, and surface-selective superconformal coatings, those that fill or coat cavities.Bottom-up approaches could eliminate the aforementioned problems while reducing the needed steps for surface-selective treatments-instead of breaking or carving things smaller and using miniaturized techniques (top-down), coatings could be grown self-aligning (bottom-up). One bottom-up category is surface-shape-selective deposition. Currently, this category has limited approaches, which are often based on either anisotropic processes such as directional plasma etching [26] or reagent flux, force fields, [27] competitive adsorption, [28] or reagents and additives with specific properties. [22] Truly bottom-up gap-filling technologies, especially those free of line-of-sight limitations, Nanotechnology drives technological progress in many frontiers, from electronics to medicine, from tougher composites to adaptive surfaces. As the feature sizes are made smaller, the importance of surfaces is increased. Many of the most powerful methods for surface manipulation are variants of vapor deposition (VD). However, VD is typically not surface-selective and, therefore, extra work steps are needed to integrate the methods into nanofabrication routines. Furthermore, many fields are moving toward 3D nanostructures, which unavoidably means...

show abstract

“…As an alternative method, in this work, we report a facile and novel approach to produce hollow mesoporous silica microspheres (HMSMs) by spray-drying of colloidal silica nanoparticles and EUT nanospheres as templates, followed by calcination to remove the templates. As a synthetic approach, this gas-phase method has several advantages over other conventional liquid process routes, such as simple fabrication steps, fast particle production, and continuous operation to produce spherical particles. , Because the dried samples leaving the furnace were collected using membrane filters, no tedious separation procedures were needed . Interestingly, because after atomization of the suspension, each droplet may be regarded as an individual microreactor while passing through the furnace, the aggregation of the resulting particles can be significantly suppressed. , More importantly, the internal structure of the hollow cavity and the external morphology and the porosity of the mesoporous shell can be finely tuned to optimize the drug loading capacity and the controlled-release properties.…”

Section: Introductionmentioning

confidence: 99%

Aerosol-Assisted Synthesis of Tailor-Made Hollow Mesoporous Silica Microspheres for Controlled Release of Antibacterial and Anticancer Agents

Poostforooshan

Belbekhouche

Shaban

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Hollow mesoporous silica microsphere (HMSM) particles are one of the most promising vehicles for efficient drug delivery owing to their large hollow interior cavity for drug loading and the permeable mesoporous shell for controlled drug release. Here, we report an easily controllable aerosol-based approach to produce HMSM particles by continuous spray-drying of colloidal silica nanoparticles and Eudragit/Triton X100 composite (EUT) nanospheres as templates, followed by template removal. Importantly, the internal structure of the hollow cavity and the external morphology and the porosity of the mesoporous shell can be tuned to a certain extent by adjusting the experimental conditions (i.e., silica to EUT mass ratio and particle size of silica nanoparticles) to optimize the drug loading capacity and the controlled-release properties. Then, the application of aerosol-synthesized HMSM particles in controlled drug delivery was investigated by loading amoxicillin as an antibiotic compound with high entrapment efficiency (up to 46%). Furthermore, to improve the biocompatibility of the amoxicillin-loaded HMSM particles, their surfaces were functionalized with poly(allylamine hydrochloride) and alginate as biocompatible polymers via the layer-by-layer assembly. The resulting particles were evaluated toward Escherichia coli (Gram-negative) bacteria and indicated the bacterial inhibition up to 90% in less than 2 h. Finally, we explored the versatility of HMSMs as drug carriers for pancreatic cancer treatment. Because the pH value of the extracellular medium in pancreatic tumors is lower than that of the healthy tissue, chitosan as a pH-sensitive gatekeeper was grafted to the HMSM surface and then loaded with a pro-apoptotic NCL antagonist agent (N6L) as an anticancer drug. The obtained particles exhibited pH-responsive drug releases and excellent anticancer activities with inhibition of cancer cell growth up to 60%.

show abstract

Aerosol Process for theIn SituCoating of Nanoparticles with a Polymer Shell

Cited by 17 publications

References 49 publications

Post-Plasma SiOx Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications

Post-Plasma SiOx Coatings of Metal and Metal Oxide Nanoparticles for Enhanced Thermal Stability and Tunable Photoactivity Applications

Condensation‐Controlled Toposelective Vapor Deposition in Nano‐ and Microcavities: Theory, Methods, Applications, and Related Technologies

Aerosol-Assisted Synthesis of Tailor-Made Hollow Mesoporous Silica Microspheres for Controlled Release of Antibacterial and Anticancer Agents

Contact Info

Product

Resources

About