Hydrogen-Bonded Organic Frameworks for Controlled Volatile Release
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Solution Overview
Problem
Current methods for controlled release of volatile compounds face challenges with control of morphology and pore size, environmental harm, and inefficiency in existing porous materials like polymers, zeolites, MOFs, and COFs, particularly in achieving gradual and environmentally friendly release.
Innovation Solution
Hydrogen-bonded organic frameworks (HOFs) with weak hydrogen-bond connections provide a modular, lightweight, thermally stable, and biodegradable solution, allowing for adjustable pore size and release rate through reversible structural transformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If microencapsulation is used for volatile compound storage, then the volatile compounds can be encapsulated and released, but the control of morphology and pore size is difficult and the host is often environmentally harmful
Solution Approach 1:
The patent employs porous organic frameworks (POFs) as the host material for encapsulating volatile compounds. These frameworks provide well-defined pore sizes and morphologies that can be precisely controlled during synthesis, eliminating the difficulty of controlling pore dimensions in traditional microencapsulation. The porous structure allows for systematic tuning of pore size to match specific guest molecule requirements while maintaining structural integrity.
Solution Approach 2:
The patent utilizes composite porous organic frameworks composed of organic building blocks linked through strong covalent bonds. This composite approach combines the advantages of organic materials (environmental friendliness, tunability) with the structural stability needed for controlled release. The frameworks are designed to be environmentally benign alternatives to traditional polymeric capsules while providing superior control over morphology and pore architecture.
2Speed
If volatile compounds are released quickly, then the immediate effect is strong, but the shelf-life and effectiveness are short-lived
Solution Approach 1:
The patent implements dynamic control of volatile release through porous organic frameworks that can adjust their release rate in response to environmental conditions. The frameworks possess flexible pore structures that can open or close based on humidity, temperature, or other stimuli, enabling the system to transition between rapid release (for immediate effect) and slow release (for extended shelf-life). This dynamic behavior allows optimization of both speed and duration of action.
Solution Approach 2:
The patent employs parameter changes in the framework structure to control release kinetics. By modifying pore size, surface area, and functional groups within the porous organic framework, the release rate can be precisely tuned. Larger pores facilitate faster release for immediate effects, while smaller pores with appropriate functional groups enable slow, sustained release for extended effectiveness. The framework's physical and chemical parameters can be adjusted to match specific application requirements.
3Stability of the object's composition
If strong bonds are used in porous frameworks, then the structure is stable, but the release control and reversibility are reduced
Solution Approach 1:
The patent divides the framework into modular units connected by reversible bonds. The porous organic framework is constructed from discrete building blocks linked through hydrogen bonds or other reversible interactions. This segmentation allows the framework to maintain overall structural stability while enabling local reversibility for controlled release. Individual modules can open and close independently, providing both stability and adaptability.
Solution Approach 2:
The patent introduces intermediary functional groups within the porous framework that mediate between the stable framework structure and the volatile guest molecules. These intermediary groups form reversible interactions with the guests, allowing controlled release while maintaining framework integrity. The intermediaries act as switching mechanisms that can bind and release guests in response to environmental stimuli, bridging the gap between structural stability and release reversibility.
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
HOFs enable controlled and extended release of volatile guests, offering eco-friendly delivery of pesticides, fragrances, and other compounds, with adjustable release rates from minutes to months, suitable for various applications.
Implementation Method 1
HOFs have weak hydrogen-bond connections between discrete building blocks
Implementation Method 2
the large surface area and large pore size, overcome some of the limitations of polymeric capsules
Data Source
AI summary
A porous framework in the form of a crystalline powder for gradual release of an active guest compound, such as volatile guests. The porous framework comprises a 3-dimensional host matrix of interconnected pores and open channels configured to house a guest compound, wherein said host matrix comprises a hydrogen-bonded organic framework (HOF) defining the pores and channels in which the guest is housed. Methods for delivering active guest compounds over time using the HOFs.