Optical Article Anti-fouling Coating via Segmented Silane Deposition
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Solution Overview
Problem
Existing methods for producing optical articles, such as ophthalmic lenses, with improved anti-smudge and anti-fouling properties are costly and do not effectively enhance durability without increasing the thickness of topcoat layers, which are made from high molecular weight sophisticated molecules.
Innovation Solution
A method involving the sequential deposition of two distinct silane materials, M1 and M2, in a vacuum chamber under reduced pressure and elevated temperature, where M1 forms a covalent bond with the substrate and M2 contributes hydrophobic or oleophobic properties, anchoring the molecules permanently for improved surface energy reduction and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the topcoat layer is increased to improve hydrophobicity and oleophobicity, then anti-fouling properties are enhanced, but production costs increase significantly
Solution Approach 1:
The topcoat layer is segmented into two distinct functional layers: a first layer containing high molecular weight fluorosilane compounds (1000-10000 g/mol) that provide durable hydrophobicity, and a second layer containing low molecular weight fluorosilane compounds (100-700 g/mol) that enhance oleophobicity. This segmentation allows each layer to contribute specific properties, achieving superior anti-fouling performance without requiring excessive total thickness that would increase cost.
Solution Approach 2:
The invention uses a composite structure combining two different fluorosilane compound classes with distinct molecular weights and properties. The first layer uses high molecular weight compounds for durability and hydrophobicity, while the second layer uses low molecular weight compounds for oleophobicity. This composite approach optimizes the functional properties per unit thickness, reducing the need for thick coatings and associated costs.
2Duration of action of stationary object
If high molecular weight fluorosilane compounds are used to improve durability of hydrophobicity, then anti-fouling durability is enhanced, but the complexity of materials increases
Solution Approach 1:
The material system is segmented into two distinct molecular weight ranges, allowing the high molecular weight component (1000-10000 g/mol) to specifically address durability requirements while the low molecular weight component (100-700 g/mol) addresses oleophobicity. This segmentation simplifies the selection process by defining clear molecular weight ranges for each functional requirement, reducing overall material complexity despite using sophisticated molecules.
3Reliability
If low molecular weight fluorosilane compounds are used to reduce surface energy, then oleophobicity is improved, but durability of the coating decreases
Solution Approach 1:
The coating is segmented into two layers where the first layer (high molecular weight fluorosilanes) provides the durable foundation with hydrophobic properties, and the second layer (low molecular weight fluorosilanes) is applied subsequently to enhance oleophobicity. The segmentation ensures that the durable high molecular weight layer remains intact while the low molecular weight layer provides additional surface energy reduction for oil resistance.
Solution Approach 2:
The high molecular weight fluorosilane layer acts as an intermediary foundation that provides durability and hydrophobicity, upon which the low molecular weight fluorosilane layer is applied to achieve enhanced oleophobicity. This intermediary layer prevents the direct exposure of the brittle low molecular weight compounds to mechanical stress, thereby preserving coating durability while achieving superior oleophobic properties.
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 achieves superior hydrophobicity and oleophobicity with enhanced durability of the optical articles, reducing surface energy and improving anti-fouling properties without significantly increasing production costs, as demonstrated by the comparison with prior art methods.
Implementation Method 1
comprising at least one function bonded to the silicon atom capable of forming a covalent bond with a substrate bearing -OH groups
Implementation Method 2
exposing at least one face of the substrate to at least two distinct materials in a chamber under conditions possibly resulting in the deposition of a layer of those materials on the surface of the substrate
Implementation Method 3
in a chamber under conditions possibly resulting in the deposition of a layer of those materials on the surface of the substrate
Data Source
AI summary
The present invention is dedicated to a method for the manufacture of an optical article comprising the following steps: providing a substrate having two main faces and bearing -OH functions on at least one of its faces, successively exposing one face of the substrate bearing -OH functions to at least 2 distinct materials named M1 and M2, M1 having a weight average molecular weight higher than M2, in a vacuum chamber under conditions resulting in the deposit of those materials on the surface of the substrate, and wherein: M1 is a substituted silane comprising: at least one function X1 bonded to a silicon atom, wherein the Si-X1 group is capable of forming a covalent bond with a -OH group of the substrate and/or a covalent bond with M2, and at least one fluorine containing group, M2 is a substituted silane having a number average molecular weight inferior or equal to 900 g/mol, comprising: at least one function X2 bonded to a silicon atom, wherein the Si-X2 group is capable of forming a covalent bond with a -OH group of the substrate and/or a covalent bond with M1, and at least one hydrophobic and/or oleophobic group, or at least one hydrophilic group, wherein the difference between the weight average molecular weight of M1 and the weight average molecular weight of M2 is higher than or equal to 600 g/mol.