Silicone Hydrogel Contact Lens Surface Hydrophilicity via Surfactant Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for improving the hydrophilicity of silicone hydrogels used in contact lenses, such as plasma treatment and surfactant impregnation, face challenges like requiring large-scale equipment, short-term wettability, affecting mechanical properties, and surfactant release, leading to reduced surface hydrophilicity.
Innovation Solution
A curable composition containing specific amounts of a silicone-based (meth)acrylate, hydrophilic monomer, and surfactant is used, which is molded with a hydrophobic mold and washed to produce a silicone hydrogel without plasma treatment, ensuring long-term surface hydrophilicity and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma treatment is used to improve surface hydrophilicity, then surface hydrophilicity is improved, but device complexity and manufacturing cost increase due to requiring large-scale equipment
Solution Approach 1:
The invention extracts the surfactant from post-processing steps and incorporates it directly into the curable composition before molding. This allows the hydrophilic surface to be formed during the molding process itself, eliminating the need for separate plasma treatment equipment and complex post-processing systems.
Solution Approach 2:
The surfactant is added to the curable composition in advance before molding, so that the hydrophilic surface is formed during the molding process rather than requiring subsequent treatment. This preliminary incorporation of the surfactant eliminates the need for complex post-processing equipment.
2Reliability
If surfactant is attached to contact lens surface after molding, then surface hydrophilicity is improved, but duration of action is short due to surfactant release
Solution Approach 1:
The invention merges the surfactant with the silicone hydrogel matrix by incorporating it into the curable composition before curing. This integration ensures the surfactant remains part of the lens structure throughout its service life, preventing release and maintaining long-term surface hydrophilicity.
Solution Approach 2:
The invention creates a composite material system where the surfactant is embedded within the silicone hydrogel matrix. This composite structure ensures the surfactant remains integrated during wear and storage, maintaining surface hydrophilicity over the entire service life of the contact lens.
3Reliability
If amphiphilic substance is copolymerized with raw materials, then surface hydrophilicity is improved, but mechanical properties are affected
Solution Approach 1:
The invention extracts the amphiphilic substance from the polymerization reaction system and uses it as a separate surfactant added to the curable composition. This allows surface hydrophilicity to be improved without the amphiphilic substance interfering with the polymerization process or affecting the mechanical properties of the silicone hydrogel.
Solution Approach 2:
The invention applies the surfactant locally to the surface region where it is needed for hydrophilicity, rather than incorporating it throughout the entire bulk material. This localized application maintains surface hydrophilicity while preserving the mechanical properties of the bulk silicone hydrogel.
4Ease of manufacture
If polypropylene mold is used for molding, then ease of manufacture is improved, but surface hydrophilicity is reduced due to hydrophobic mold surface
Solution Approach 1:
The invention converts the harmful effect of the hydrophobic polypropylene mold surface into a beneficial process by adding a surfactant to the curable composition. The surfactant compensates for the hydrophobic mold surface, allowing the silicone monomer to polymerize uniformly and form a hydrophilic surface despite the hydrophobic molding material.
Solution Approach 2:
The invention introduces a surfactant as an intermediary substance between the hydrophobic mold surface and the silicone monomer. This surfactant mediator allows the silicone monomer to access and polymerize on the hydrophobic mold surface while still forming a hydrophilic surface structure in the final product.
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 produces a silicone hydrogel with excellent surface hydrophilicity and transparency that remains stable over time, suitable for contact lenses and other eye devices without the need for additional surface treatments.
Implementation Method 1
a curable composition containing a silicone-based (meth)acrylate, a hydrophilic monomer, and a surfactant
Implementation Method 2
the surfactant is attached to the surface of the contact lens
Implementation Method 3
a silicone monomer polymerizes in a segregated state on the mold surface
Implementation Method 4
a curable composition containing a silicone-based (meth)acrylate, a hydrophilic monomer, and a surfactant
Data Source
Figure 1
Figure 2
AI summary
A method for producing a silicone hydrogel includes the following steps (1) to (3): a step (1): a step of preparing a curable composition containing a silicone-based (meth)acrylate (A), a hydrophilic monomer (B), and a surfactant (C); a step (2): a step of molding the curable composition with a hydrophobic mold to obtain a cured product; and a step (3): a step of washing the cured product.