Core-Shell Zinc Oxide Particles UV Shielding
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Solution Overview
Problem
Conventional core-shell zinc oxide particles lack effective UV light-shielding capabilities due to agglomeration and poor dispersibility, particularly failing to adequately protect against UVA radiation, which is a leading cause of skin cancer.
Innovation Solution
A method involving the sequential mixing and heating of calcium-containing materials with zinc ammonia complex salt solutions, followed by calcination, to produce core-shell zinc oxide particles with enhanced UV light-shielding properties by increasing the reflective area of zinc oxide flakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If zinc oxide powder is used to shield UV light, then UV protection capability is improved, but dispersibility deteriorates due to high polarity causing agglomeration
Solution Approach 1:
The patent creates a core-shell composite structure where zinc oxide forms a shell around a hydrophobic core particle. This composite structure combines the UV-shielding properties of zinc oxide with the dispersibility benefits of the hydrophobic core, resolving the contradiction between UV protection and dispersibility.
Solution Approach 2:
The patent applies local quality modification by coating only the surface of core particles with zinc oxide, creating a shell layer. This allows the core to maintain hydrophobicity for dispersibility while the shell provides UV shielding, addressing both requirements simultaneously.
2Stability of the object's composition
If conventional core-shell zinc oxide particles are prepared, then dispersibility is improved, but UV light-shielding effect deteriorates due to insufficient reflective area
Solution Approach 1:
The patent changes the morphology parameter of zinc oxide from conventional spherical or cubic shapes to flake-shaped structures. This morphological change increases the reflective area of the zinc oxide particles, enhancing UV light-shielding effect while maintaining the core-shell structure for dispersibility.
Solution Approach 2:
The patent transitions zinc oxide morphology to two-dimensional flake structures, increasing the surface area and reflective area in comparison to zero-dimensional particles. This dimensional change enhances UV shielding capability without compromising dispersibility.
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 method results in core-shell zinc oxide particles that exhibit improved UV light-shielding effects, reflecting more UV light and providing better protection against both UVA and UVB radiation compared to conventional methods.
Implementation Method 1
heating the first mixture to remove ammonia, thereby obtaining a first intermediate product
Implementation Method 2
calcining the second intermediate product to obtain core-shell zinc oxide particles
Implementation Method 3
zinc oxide that is capable of shielding both UVA and UVB
Implementation Method 4
materials that are effective in shielding UV light (i.e. reflecting UV light)
Data Source
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AI summary
A method of preparing core-shell zinc oxide particles, includes: mixing a calcium-containing material with a first zinc ammonia complex salt solution to obtain a first mixture; heating the first mixture to remove ammonia, thereby obtaining a first intermediate product; mixing the first intermediate product with a second zinc ammonia complex salt solution to obtain a second mixture; heating the second mixture to remove ammonia, followed by conducting a drying process to obtain a second intermediate product; and calcining the second intermediate product to obtain the core-shell zinc oxide particles. A core-shell zinc oxide particle is prepared by the aforementioned method, and a composition for shielding ultraviolet light includes the core-shell zinc oxide particles.