Vinyl Epoxy Polysiloxanes for Contact Lens Wettability
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Solution Overview
Problem
Silicone hydrogel materials for contact lenses often have hydrophobic, non-wettable surfaces, which can lead to discomfort and adverse reactions such as corneal edema and inflammation, necessitating increased hydrophilicity to improve wettability and wear comfort.
Innovation Solution
Polysiloxanes with vinyl or epoxy functionality are used to create polysiloxane prepolymers that can be modified to introduce reactive sites on the surface of silicone materials, allowing for attachment of hydrophilic polymers or other organic compounds to enhance surface hydrophilicity and modify chemical or physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicone hydrogel materials are used for contact lenses, then oxygen permeability is improved, but surface hydrophilicity deteriorates (hydrophobic, non-wettable surfaces)
Solution Approach 1:
The patent applies local quality by introducing vinyl or epoxy functional groups at specific locations within the polysiloxane structure (at siloxane units along the chain), creating localized reactive sites that can be selectively modified to enhance surface hydrophilicity while preserving the bulk material's high oxygen permeability characteristics
Solution Approach 2:
The patent creates composite materials by combining polysiloxane backbone structures with hydrophilic polymer chains through chemical modification of vinyl or epoxy groups, resulting in a composite hydrogel material that exhibits both high oxygen permeability (from the silicone component) and improved surface wettability (from the hydrophilic polymer component)
2Object-affected harmful factors
If hydrophilic polymer chains are attached to increase surface hydrophilicity, then wettability is improved, but material complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating vinyl or epoxy functional groups into the polysiloxane structure during the base polymer synthesis, preparing reactive sites in advance that can subsequently react with hydrophilic monomers. This pre-prepared reactivity simplifies the overall modification process compared to attempting to attach hydrophilic chains to inert silicone surfaces
Solution Approach 2:
The patent employs parameter changes by adjusting the concentration and type of vinyl or epoxy functional groups within the polysiloxane structure to optimize the balance between maintaining oxygen permeability and achieving sufficient reactivity for hydrophilic polymer attachment, thereby controlling the degree of material complexity
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 approach results in silicone hydrogel materials with improved wettability, reduced haze, and enhanced oxygen permeability, providing better comfort and reducing the risk of adverse reactions, while maintaining high oxygen permeability and flexibility.
Implementation Method 1
The vinyl or epoxy functional groups, which can be positioned at a plurality of siloxane units along a length of the polysiloxane, provide a plurality of reactive sites on a surface of a polymeric silicone material for attachment of hydrophilic polymer chains or other organic compounds
Data Source
AI summary
Polysiloxanes having vinyl or epoxy functionality. The polysiloxanes are used to form polymer-based materials having properties particularly suited for biomedical device applications. The polysiloxanes are of general formula I:whereinR is a C2-10 alkenyl, a C2-10 alkyl with an epoxy group or a C5-C7cycloalkyl with an epoxy group;R2, R3 and R4 are each independently selected from the group consisting of hydrogen, C1-4 alkyl, C1-4 fluoroalkyl, optionally substituted phenyl and optionally substituted benzyl;A is —OH or —NHR5, wherein R5 is hydrogen or a C1-3 alkyl; andB is —R1-A or —R6, wherein R1 is a linking group having an alkylene group with 2 to 8 carbon atoms wherein the alkylene group optionally includes ether, urethane or ureido linkages; and R6 is selected from the group consisting of C1-4 alkyl, optionally substituted phenyl or optionally substituted benzyl; andm and n are integers with an m:n ratio from 30:1 to 3:1.