Silver Nano-Particles on Silica Carrier for Suspension Stability

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Solution Overview

Problem

Existing methods for producing metallic silver nano-particles often result in agglomerates that reduce the active surface area and stability of suspensions, leading to undesirable effects such as reduced homogeneity and mechanical properties in final products.

Innovation Solution

A powder composed of silica carrier grains with metallic silver nano-particles, where at least 95% of the silica grains are between 450 and 650 nm and 95% of the silver nano-particles are between 0 and 20 nm, is produced using a method involving the reaction of tetraethyl orthosilicate and aqueous ammonia, followed by centrifugation, sonication, and reduction with hydrogen at elevated temperatures, ensuring a narrow size range and improved homogeneity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If metallic silver nano-particles are produced using conventional methods, then the production process is simple, but the nano-particles form agglomerates that reduce active surface area and suspension stability

Engineering Contradiction:
Improveproduction process simplicityVSAvoidsuspension stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a silica carrier as an intermediary substance to support the metallic silver nano-particles. The silica carrier prevents direct contact between silver nano-particles, thereby preventing agglomeration while maintaining suspension stability. This mediator approach resolves the contradiction by introducing a third component that facilitates particle dispersion without complicating the overall manufacturing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite material consisting of silica carrier grains with surface-conjugated metallic silver nano-particles. This composite structure combines the benefits of both materials: the silica provides structural support and prevents agglomeration, while the silver nano-particles provide the desired functional properties. The composite approach maintains ease of manufacture while significantly improving suspension stability.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If metallic silver nano-particles are produced using conventional methods, then the production process is simple, but the active surface area is reduced due to agglomerate formation

Engineering Contradiction:
Improveproduction process simplicityVSAvoidactive surface area
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The silica carrier acts as a mediator that physically separates silver nano-particles, preventing them from forming agglomerates. This separation maintains the high surface area to volume ratio of individual nano-particles, thereby preserving the active surface area needed for catalytic and functional applications while keeping the production process relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention applies local quality by concentrating silver nano-particles on the surface of silica carrier grains rather than distributing them freely. This localized arrangement ensures that each silver particle maintains its small size and high surface area, while the silica carrier provides a structured framework that prevents bulk agglomeration.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If the silica carrier grain size is reduced to increase surface area, then the active surface area increases, but the mechanical properties and steam permeability of final products deteriorate

Engineering Contradiction:
Improvesurface areaVSAvoidmechanical properties
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The patent optimizes the silica carrier grain size to a specific range (450-650 nm) that balances surface area requirements with mechanical property preservation. This parameter optimization ensures sufficient surface area for nano-particle conjugation while maintaining the structural integrity and steam permeability needed for industrial applications in textiles, paints, and cosmetics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by concentrating the nano-scale silver particles on the surface of appropriately-sized silica carriers. This allows the bulk silica material to maintain its mechanical strength and permeability properties, while the surface provides the necessary surface area for high-density silver particle attachment and enhanced functionality.

Inventive Principle:
Principle #3Local quality

4Area of stationary object

If the silver nano-particle size is minimized to increase surface area, then the active surface area increases, but the homogeneity and stability of the powder become difficult to maintain

Engineering Contradiction:
Improvesurface areaVSAvoidhomogeneity
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The silica carrier serves as a mediator that provides a uniform support structure for silver nano-particles. This standardized carrier framework enables consistent distribution and sizing of silver particles, improving manufacturing precision and homogeneity while maintaining the high surface area benefits of minimized particle size.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the silver nano-particle size to a specific range (0-20 nm) that maximizes surface area while maintaining homogeneity and stability. This parameter control, combined with the silica carrier support system, ensures that the powder maintains consistent properties suitable for industrial applications.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting powder exhibits enhanced stability, homogeneity, and mechanical properties, allowing for industrial-scale production and use in various applications like textiles, paints, and cosmetics without compromising mechanical durability or steam permeability.

Implementation Method 1

a colloidal suspension of SiO2 is produced during a reaction of tetraethyl orthosilicate and aqueous ammonia

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

a colloidal suspension of SiO2 is produced during a reaction of tetraethyl orthosilicate and aqueous ammonia

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

the resulting silica is centrifuged off at 6 000 G to 25 000 G

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 4

the resulting silica is centrifuged off at 6 000 G to 25 000 G, and is subsequently treated with ultrasounds

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 5

the silver nitrate is reduced with hydrogen at a temperature in excess of 300°C

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 6

the silver nitrate is reduced with hydrogen at a temperature in excess of 300°C

Methodology Applied
Scientific EffectRedox reactions: Redox Reactions

Implementation Method 7

the silver nitrate is reduced with hydrogen at a temperature in excess of 300°C

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP2244973B1A powder composed of metallic silver nano-particles surface- conjugated with a silica carrier, a method of its manufacture and use
Publication Date: 2012.03.07 POCH

AI summary

The present invention relates to a novel material composed of metallic silver nano- particles surface-conjugated with a silica carrier, a method of its manufacture and its use. The product produced may be manufactured on an industrial scale and be used in many areas, among others in the textile, pharmaceutical, chemical, plastics, food and coatings industries.