Dual-Reactive Cross-Linking Agents for Hydrogel Stability
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Solution Overview
Problem
Current cross-linking agents for hydrogel materials, particularly those used in contact lenses, face challenges such as volatility, incompatibility of silicone-based monomers with hydrophilic monomers, and instability, leading to inconsistent crosslinking, phase separation, and reduced mechanical properties like lubricity and dimensional stability.
Innovation Solution
Development of dual-reactive cross-linking agents that react with both (meth)acrylate and vinyl monomers, providing consistent crosslinking and enhancing the mobility of hydrophilic vinyl polymer chains within the hydrogel framework, thereby improving the hydrogel's mechanical properties and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cross-linking agents are used to form hydrogel networks, then crosslinking is achieved, but volatility and instability occur leading to inconsistent crosslinking and reduced mechanical properties
Solution Approach 1:
The patent modifies the chemical structure of cross-linking agents by changing parameters such as molecular weight, functional group composition, and reactivity characteristics. This results in cross-linking agents with reduced volatility and improved stability while maintaining effective crosslinking capability, thereby resolving the contradiction between crosslinking consistency and volatility.
Solution Approach 2:
The patent employs composite cross-linking systems combining multiple cross-linking agents or integrating cross-linking agents with complementary functional groups. This composite approach provides more consistent crosslinking patterns and reduces the harmful effects of individual agent volatility, improving overall reliability while mitigating harmful factors.
2Reliability
If silicone-based monomers are incorporated with hydrophilic monomers, then oxygen permeability is improved, but phase separation occurs reducing mechanical properties
Solution Approach 1:
The patent introduces compatibilizing agents or intermediary molecules that facilitate compatible interaction between silicone-based and hydrophilic monomers. These intermediaries act as molecular bridges, enabling uniform distribution and preventing phase separation while maintaining the mechanical stability and oxygen permeability benefits of both monomer types.
Solution Approach 2:
The patent adjusts compositional parameters such as monomer ratios, cross-linking density, and functional group distributions to optimize compatibility between silicone and hydrophilic components. By carefully controlling these parameters, the patent achieves homogeneous mixture stability while preserving the mechanical properties and oxygen permeability advantages.
3Strength
If cross-link density is increased to improve mechanical properties, then strength is improved, but water content decreases
Solution Approach 1:
The patent implements non-uniform cross-linking strategies where cross-link density varies in different regions or types of bonds within the hydrogel network. By creating local variations in cross-linking (e.g., different cross-link densities in different spatial zones or bond types), the patent achieves adequate mechanical strength through localized reinforcement while preserving water content in other regions through controlled porosity or hydrophilic pathways.
Solution Approach 2:
The patent employs composite hydrogel systems combining multiple polymer matrices with different cross-linking characteristics. This allows different regions of the composite material to have different cross-link densities - some regions providing mechanical strength while others maintaining high water content, thus resolving the contradiction between strength and water content.
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 dual-reactive cross-linking agents achieve a hydrogel with enhanced water content, improved lubricity, dimensional stability, and oxygen permeability, ensuring a comfortable and durable contact lens with consistent performance.
Implementation Method 1
these crosslinks can be formed by covalent bonds, electrostatic, hydrophobic, or dipole-dipole interactions
Implementation Method 2
these crosslinks can be formed by covalent bonds, electrostatic, hydrophobic, or dipole-dipole interactions
Implementation Method 3
these crosslinks can be formed by covalent bonds, electrostatic, hydrophobic, or dipole-dipole interactions
Implementation Method 4
these crosslinks can be formed by covalent bonds, electrostatic, hydrophobic, or dipole-dipole interactions
Implementation Method 5
a balance between an osmotic force that drives the water to enter the hydrophilic polymer network
Implementation Method 6
an osmotic force that drives the water to enter the hydrophilic polymer network
Implementation Method 7
a cohesive force exerted by the polymer chains in resisting expansion
Implementation Method 8
One class of conventional synthetic hydrogels is prepared by free-radical polymerization of vinyl or (meth)acrylate monomers using thermal or photo initiators
Implementation Method 9
free-radical polymerization of vinyl or (meth)acrylate monomers using thermal or photo initiators
Data Source
AI summary
Cross-linking agent(s), composition(s) made therefrom and use(s) thereof. For example, crosslinking agent(s) that are used to make composition(s) such as hydrogel material(s). Such materials are useful in the manufacture of biocompatible medical devices, for example, hydrogel materials having desirable physical properties for use as contact lense(s) and/or stimulating device(s).