Cross-linked polymeric materials, methods of their preparation and uses thereof
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Solution Overview
Problem
Current antimicrobial coatings and surfaces face challenges such as water solubility, high cost, and poor mechanical properties, and existing methods for preparing antimicrobial surfaces often require harsh chemical reactions or extensive washing to remove residual toxic monomers and photoinitiators, while also lacking effective cross-linking of polymers.
Innovation Solution
A method involving the irradiation of polymers with aliphatic primary amine moieties in the presence of oxygen and a sensitizer to form imine cross-links, using polymers like polysiloxanes, polysaccharides, or polyamides, which can be deposited on surfaces and treated with visible light to generate reactive oxygen species for antimicrobial activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photopolymerization methods (acrylate or thiol-ene UV chemistry) are used for cross-linking, then cross-linking efficiency is improved, but residual toxic monomers and photoinitiators remain requiring extensive washing
Solution Approach 1:
The patent extracts and eliminates the harmful components (toxic monomers and photoinitiators) from the cross-linking system by using an alternative photocatalytic mechanism that relies on singlet oxygen generation from a sensitizer rather than traditional photoinitiators, thereby removing the source of residual toxicity while maintaining cross-linking efficiency
Solution Approach 2:
The patent changes the chemical parameters of the cross-linking reaction by shifting from radical-based photopolymerization to singlet oxygen-mediated oxidative coupling, using visible light sensitizers instead of UV photoinitiators, and employing environmentally benign conditions that eliminate harmful residues
2Reliability
If polymers are deposited on surfaces for antimicrobial coating, then antimicrobial coverage is improved, but water solubility and mechanical properties deteriorate
Solution Approach 1:
The patent applies preliminary cross-linking of the polymer coating before it can be washed away by water, using visible light irradiation to trigger singlet oxygen generation that oxidatively couples amine groups, thereby anchoring the coating to the surface and preventing water solubility issues before they occur
Solution Approach 2:
The patent creates a composite structure by cross-linking the polymer coating to form a unified network that combines the antimicrobial properties of the deposited polymer with enhanced mechanical strength from the cross-linked network, preventing delamination and improving durability
3Reliability
If harsh chemical reactions are used for surface treatment, then cross-linking is achieved, but process complexity and environmental impact increase
Solution Approach 1:
The patent replaces harsh chemical cross-linking methods with a photochemical process using visible light and singlet oxygen generation, substituting mechanical/chemical intensity with optical energy to achieve cross-linking under milder, more environmentally friendly conditions
Solution Approach 2:
The patent employs a self-service mechanism where atmospheric oxygen serves as the oxidant for cross-linking, eliminating the need for external chemical reagents, and the sensitizer catalyst is regenerated during the reaction cycle, reducing process complexity and environmental impact
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
This approach results in cross-linked polymeric materials with enhanced mechanical properties and antimicrobial efficacy, providing passive contact killing and active photodynamic inactivation against pathogens, with minimal leaching and impact on surface properties.
Implementation Method 1
Singlet oxygen (1O2) is a reactive oxygen species that can be photogenerated through oxygen quenching of the triplet excited state of sensitizing molecules
Implementation Method 2
irradiating a polymer comprising a plurality of aliphatic primary amine moieties or precursors thereto in the presence of oxygen and a sensitizer to form imine cross-links via the oxidative coupling of at least a portion of the aliphatic primary amine moieties
Data Source
AI summary
The present disclosure relates to methods for preparing cross-linked polymeric materials, cross-linked polymeric materials which can be prepared by such methods and uses of such cross-linked polymeric materials, for example, as antibacterial surfaces or coatings. The present disclosure also relates to polymers such as the polymer of the general Formula (III) which can be used, for example, to prepare such cross-linked polymeric materials: