Siloxane Contact Lens Material for Oxygen Permeability and Hydrophilicity
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Solution Overview
Problem
Hydrogel contact lenses face challenges in achieving high oxygen permeability and water content without compromising surface hydrophilicity, leading to issues like bacterial growth and eye inflammation.
Innovation Solution
A contact lens material comprising a siloxane monomer, hydrophilic monomer, crosslinking agent, and initiator, with specific molecular structures and proportions, enhancing oxygen permeability and surface hydrophilicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrophilic monomers are added to increase water content, then water content increases, but tension and toughness decrease
Solution Approach 1:
The patent optimizes the ratio of hydrophilic monomers to crosslinking agents and adjusts the molecular weight and structure of the hydrogel material to achieve the optimal balance between water content (60-75%) and mechanical strength (tension and toughness).
Solution Approach 2:
The patent creates a composite hydrogel material combining multiple hydrophilic monomers (NVP, DMA, MAA) with crosslinking agents in specific proportions to achieve both high water content and adequate mechanical properties through synergistic effects.
2Reliability
If water content is increased to improve comfort, then oxygen permeability increases, but surface hydrophilicity decreases leading to bacterial growth
Solution Approach 1:
The patent modifies the surface properties of the contact lens through surface treatment or by incorporating amphiphilic molecules that provide hydrophilic surfaces while maintaining high oxygen permeability in the bulk material.
Solution Approach 2:
The patent adjusts the chemical composition parameters by incorporating specific hydrophilic monomers and crosslinking agents in optimized ratios to simultaneously achieve high oxygen permeability (DK ≥ 40) and surface hydrophilicity.
3Reliability
If silicone hydrogel is used to increase oxygen permeability, then oxygen permeability increases, but surface hydrophobicity increases causing bacterial growth
Solution Approach 1:
The patent creates a core-shell structure or surface-modified silicone hydrogel where the bulk material provides high oxygen permeability while the surface layer provides hydrophilicity to prevent bacterial growth.
Solution Approach 2:
The patent introduces amphiphilic molecules or surface coating agents that act as intermediaries between the hydrophobic silicone hydrogel material and the aqueous environment, providing surface hydrophilicity while maintaining the bulk oxygen permeability.
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 contact lens material achieves high oxygen permeability (not less than 40 barrers) and water content (45-80 wt%) with improved surface hydrophilicity, reducing the need for additional coatings and ensuring better eye compatibility.
Implementation Method 1
The contact lens material achieves high oxygen permeability (not less than 40 barrers)
Implementation Method 2
Hydrogel contact lenses are made of hydrogel materials, such as poly-2-hydroxyethyl methacrylate (p-HEMA). The strength of poly-2-hydroxyethyl methacrylate (p-HEMA) can be improved by adding crosslinking agent
Implementation Method 3
The water content of the contact lenses can be effectively increased up to 70-80% by adding hydrophilic monomers
Data Source
AI summary
A contact lens material includes: a hydrophilic monomer, a crosslinking agent, an initiator, and a siloxane monomer. Based on a total weight of the contact lens material being 100 parts by weight, an amount of the siloxane monomer is between 5 parts by weight and 50 parts by weight. A chemical empirical formula of the siloxane monomer is: CaHbOcNdSie, in which C represents carbon atoms, a is a positive number between 12 and 55, H represents hydrogen atoms, b is a positive number between 29 and 121, O represents oxygen atoms, c is a positive number between 4 and 17, N represents nitrogen atoms, d is a positive number between 0 and 5, Si represents silicon atoms, and e is a positive number between 1 and 9.