Covalent Adaptable Networks With Light- and Heat-Triggered Bond Reshuffling

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Solution Overview

Problem

Existing covalent adaptable networks (CANs) face limitations in remoldability, recyclability, and coloration at ambient temperatures, lacking spatial and temporal control over bond reshuffling.

Innovation Solution

Compositions comprising multifunctional thioesters, thiols, and exchange catalysts, such as bases and nucleophiles, enable CANs to undergo bond reshuffling at ambient temperatures with controlled activation and deactivation using light and heat, allowing for remolding and recycling without degradation or discoloration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If light-triggered bond rearrangement using RAFT mechanism is used, then spatial and temporal control over plasticity is achieved, but the material cannot undergo multiple cycles, remold, or flow in bulk and experiences yellowing/coloration

Engineering Contradiction:

Improvespatial and temporal control over plasticityVSAvoidability to undergo multiple cycles and remold

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent changes the activation parameter from light to thermal stimulus, enabling the polymer network to undergo repeated bond reshuffling cycles at elevated temperatures without the degradation and coloration issues associated with light-triggered mechanisms. This allows the material to be remolded and recycled multiple times while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the photochemical RAFT mechanism with a thermally activated degenerate exchange reaction mechanism. This substitution eliminates the harmful side effects of light activation (yellowing, limited recyclability) while achieving the desired control over bond reshuffling through temperature modulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If thermally activated degenerate exchange reactions are used, then remoldability and multiple cycles are possible, but high heats (>120°C) are required and spatial control is not feasible with coloration often unavoidable

Engineering Contradiction:

Improveremoldability and multiple cyclesVSAvoidhigh heats required

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent introduces a threshold temperature parameter (e.g., 80°C) below which bond reshuffling is suppressed and above which it is activated. This allows the material to maintain dimensional stability at ambient and moderate temperatures while enabling controlled remolding at elevated temperatures, eliminating the need for excessively high heats and preventing unwanted coloration.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent establishes a temperature threshold that prevents premature bond reshuffling at lower temperatures. By designing the system to remain stable below this threshold and only activate above it, the material avoids unwanted coloration and maintains structural integrity during storage and handling, while still allowing controlled remolding when the threshold is exceeded.

Inventive Principle:

Principle #9Preliminary anti-action

3Adaptability or versatility

If thermally activated degenerate exchange reactions are used, then remoldability is achieved, but spatial control over bond reshuffling is not feasible

Engineering Contradiction:

ImproveremoldabilityVSAvoidspatial control over bond reshuffling

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent enables spatial control by creating local thermal gradients or applying heat to specific regions of the polymer network. Since bond reshuffling only occurs above the threshold temperature, localized heating allows precise control over which portions of the material undergo remolding, while other regions remain stable and maintain their original shape and properties.

Inventive Principle:

Principle #3Local quality

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 compositions provide CANs with the ability to be remolded, recycled, and repaired at ambient temperatures, offering spatial and temporal control over bond reshuffling, thus overcoming the limitations of existing CANs.

Implementation Method 1

The polymer network comprises covalent adjustable bonds formed from the reaction of a multifunctional thiol and a multifunctional thioester

Methodology Applied

Scientific EffectThiol-thioester exchange: Chemical Bonding

Implementation Method 2

The covalent bond reshuffling is triggered photolytically, wherein light can be used to activate or deactivate the bond reshuffling

Methodology Applied

Scientific EffectPhotolytic initiation: Photodissociation

Implementation Method 3

The covalent bond reshuffling is triggered thermally, wherein heat can be used to activate or deactivate the bond reshuffling

Methodology Applied

Scientific EffectThermal activation: Heating

Implementation Method 4

directional stress within the network drives the equilibrium towards a particular bond configuration to dissipate chain energy, which leads to macroscopic stress relaxation behavior

Methodology Applied

Scientific EffectStress relaxation: Stress Relaxation

Data Source

PatentEP3504251B1Network polymers and methods of making and using same

Publication Date: 2026.03.25 THE REGENTS OF THE UNIVERSITY OF COLORADO

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AI summary

The present invention relates to covalent adaptable networks (CANs) having exchangeable crosslinks which are able to undergo repeated covalent bond reshuffling through photo-activation at ambient temperatures. The invention provides covalent adaptable network forming compositions as well as methods of forming, remolding and recycling the CANs of the invention.