Interpenetrating Polymer Network Surface Modification via Supercritical CO2
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Solution Overview
Problem
Existing methods for producing interpenetrating polymer networks (IPNs) do not allow for the design of articles with pre-selected surface properties that differ from the substrate, limiting the ability to create articles with specific surface characteristics.
Innovation Solution
A method involving a polymer substrate exposed to monomers and a CO2-based solvent in a reaction chamber, where the monomers are polymerized to form an interpenetrating polymer network, allowing for the creation of articles with desired surface properties by integrating a selected polymer layer strongly onto the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional IPN production methods are used, then the basic structure is formed, but the surface properties cannot be pre-selected or differentiated from the substrate
Solution Approach 1:
The patent applies local quality by creating a surface layer with distinct properties from the substrate through selective monomer polymerization. The surface layer is formed by polymerizing monomers exposed to the substrate surface, while the bulk substrate maintains its original properties. This allows different regions of the article to have optimized properties for their specific functions.
Solution Approach 2:
The patent segments the article into two distinct parts: the original substrate and the newly formed surface layer. This segmentation is achieved by controlling the polymerization to occur primarily at the surface, creating a layered structure where each layer can be independently optimized for its specific requirements.
2Adaptability or versatility
If a polymer layer is added to the substrate surface, then surface properties are improved, but the bonding strength between layer and substrate may be insufficient
Solution Approach 1:
The patent merges the substrate and surface layer into a unified interpenetrating polymer network structure. Monomers are exposed to the substrate surface and polymerize to form a network that interpenetrates with the substrate's polymer matrix, creating strong physical and chemical bonds between the layers without requiring separate adhesive interfaces.
Solution Approach 2:
The patent creates a composite material system consisting of the original substrate polymer and the newly formed surface layer polymer. The IPN structure combines the properties of both polymers in a single integrated material, where the surface layer provides enhanced surface characteristics while maintaining strong bonding to the substrate.
3Adaptability or versatility
If multiple processing steps are used to achieve desired surface properties, then surface characteristics are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by exposing the substrate to monomers before final polymerization. The monomers are first adsorbed or absorbed onto the substrate surface, then polymerized in situ to form the surface layer. This preliminary exposure step allows for controlled surface property modification without requiring multiple subsequent processing steps.
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
Enables the production of articles with coherent, desired surface characteristics, such as altered hardness, permeability, stiffness, and hydrophilicity, by forming an interpenetrating polymer network that can be cross-linked and tailored for specific applications, such as medical devices and contact lenses.
Implementation Method 1
exposing said polymer substrate in said reaction chamber to said at least one monomer in the presence of an impregnation solvent comprising CO2 under conditions wherein said CO2 is in its liquid or supercritical state
Implementation Method 2
polymerizing said at least one monomer to form an interpenetrating polymer in the presence of a polymerization solvent under conditions wherein at least a part of said at least one monomer is dissolved in said polymerization solvent
Data Source
AI summary
The invention relates to a method of producing an article comprising an interpenetrating polymer network (IPN) and an IPN comprising article e.g. obtainable by this method. The method comprises providing a polymer substrate e.g. shaped to provide the desired article and applying it in a reaction chamber, providing at least one monomer for an interpenetrating polymer, exposing said polymer substrate in said reaction chamber to said at least one monomer in the presence of an impregnation solvent comprising CO2 under conditions wherein said CO2 is in its liquid or supercritical state and polymerizing and optionally cross linking said at least one monomer to form an interpenetrating polymer in the presence of a polymerization solvent under conditions wherein at least a part of said at least one monomer is dissolved in said polymerization solvent. The article comprises a body formed of a polymer substrate and an interpenetrating polymer of a second polymer different from the polymer of the polymer substrate and an outer surface layer on at least a part of its surface of said second polymer.