Silicone Nanoparticle Coating for Superhydrophobic Surfaces
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Solution Overview
Problem
Existing methods for imparting superhydrophobic, superoleophobic, or superamphiphobic properties to substrates, such as chemical vapor deposition and immersion techniques, are impractical for large objects and require prolonged exposure to coating compositions, leading to issues like evaporation of solvents and potential damage from acidic mediums.
Innovation Solution
A method involving a liquid coating composition with dispersed silicone nanoparticles, formed by polymerization in an aprotic solvent, is applied to the substrate, where the solvent is evaporated to create a superhydrophobic, superoleophobic, or superamphiphobic layer, allowing for efficient property imparting without the need for prolonged exposure or controlled atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical vapor deposition or immersion techniques are used to form superhydrophobic layers, then the coating can be grown on the substrate surface, but the substrate must be inserted into a controlled atmosphere container or large enough container to fully immerse the substrate
Solution Approach 1:
The patent extracts the coating-forming mechanism from the complex CVD/immersion process by pre-synthesizing silicone nanoparticles in a controlled environment, then applying them as a dispersion. This removes the need for large controlled atmosphere containers or immersion vessels, as the nanoparticles are simply applied to the substrate surface and cured in place.
2Reliability
If the substrate is immersed in coating solution for several hours to grow silicone nanofilaments, then superhydrophobic properties are achieved, but the extensive time period causes solvent and silane to evaporate before filament formation
Solution Approach 1:
The patent performs the coating formation action in advance by pre-synthesizing the silicone nanoparticles with the desired nanofilament structure before application. The nanoparticles are prepared with controlled morphology and properties, then applied as a ready-to-cure dispersion that forms the final coating rapidly on the substrate without requiring hours of immersion or evaporation time.
3Productivity
If halogenated silane monomers are used to promote polymerization, then coating formation is accelerated, but hydrochloric acid is formed during condensation reaction causing potential damage
Solution Approach 1:
The patent changes the chemical parameters of the polymerization process by using non-halogenated silane monomers (such as alkoxysilanes) instead of halogenated ones. This substitution maintains the ability to form crosslinked polymer networks and achieve coating formation, but eliminates the generation of hydrochloric acid during condensation, replacing it with alcohol byproducts that are less harmful.
4Reliability
If the substrate surface is primed before applying the coating composition, then adhesion is improved, but an additional step is required
Solution Approach 1:
The patent merges the priming function with the coating composition itself by formulating the nanoparticle dispersion with adhesion promoters and surface-active agents that provide both coating formation and substrate adhesion in a single applied layer. This combines what would traditionally be separate priming and coating steps into one unified application process.
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
This method enables the effective formation of superhydrophobic, superoleophobic, or superamphiphobic layers on substrates of any size, maintaining optical transparency and self-cleaning properties while avoiding the limitations of traditional techniques.
Implementation Method 1
a dispersed form of silicone nanoparticles, formed by polymerization in an aprotic solvent, comprising 5 to 500 ppm water of at least one compound of formula I
Implementation Method 2
the dispersed silicone nanoparticles are formed by polymerization in an aprotic solvent, preferably toluene, comprising 5 to 500 ppm, preferably 60 to 250 ppm, more preferably 75 to 150 ppm, of water
Implementation Method 3
d. evaporating the solvent from the liquid coating composition to form a superhydrophobic, superoleophobic, or superamphiphobic layer
Implementation Method 4
R. G. Smith, 'Self-assembly of silicone nanofilaments (SNFs) from sol-gel derived precursors: a route to superhydrophobic surfaces', J. Mater. Chem., 2011, 21, 1889-1898
Data Source
AI summary
A method for forming a superhydrophobic, superoleophobic or superamphiphobic layer and imparting said properties on a surface, wherein dispersed silicone nanoparticles are formed by polymerization of at least one compound of formula IRaSi(R1)n(X1)3-n (I)in an aprotic solvent comprising 5 to 500 ppm water and wherein Ra is a straight-chain or branched C(1-24) alkyl or alkenyl group, an aromatic group which is linked by a single covalent bond or linked by a straight-chain or branched alkylene unit having 1 to 8 carbon atoms, to the Si-atom, R1 a straight chain or a branched hydrocarbon radical having 1 to 6 carbon atoms, X1 is a hydrolysable group, which is one or more of a halogen or an alkoxy group, and n is 0 or 1.