Photocatalytic Covalent Attachment for Durable Substrate Modification
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Solution Overview
Problem
Existing methods face challenges in covalently attaching active materials to substrates like hair and skin, especially in the presence of water, which degrades reactive moieties and competes with covalent attachment, and substrates often lack reactive functional groups, making it difficult to achieve durable modification.
Innovation Solution
A composition comprising a silicone polymer or copolymer with functional groups capable of covalent attachment, combined with a photocatalyst that generates acid or base upon light exposure, allowing for covalent bonding with substrate functional groups, thereby modifying surface and bulk properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If covalent attachment methods are used to modify substrate surface properties, then durability and stability of modification are improved, but water degrades reactive moieties and competes with covalent attachment, reducing effectiveness
Solution Approach 1:
The photocatalyst is applied to the substrate surface in advance, and reactive moieties are introduced before water exposure. Upon light activation, covalent bonds form preliminarily protecting the modification from subsequent water degradation, thus achieving durable surface properties despite presence of water
Solution Approach 2:
The photocatalyst acts as an intermediary that enables covalent attachment through light-induced acid/base generation. This intermediary mechanism allows covalent bonding to proceed selectively on substrate surfaces even in the presence of water, which would otherwise degrade reactive moieties through hydrolysis
2Reliability
If covalent attachment is attempted on substrates like hair and skin, then durable modification is achieved, but substrates lack reactive functional groups, making attachment difficult
Solution Approach 1:
The photocatalyst changes the chemical environment parameters on the substrate surface upon light exposure by generating acid or base. This parameter change creates reactive conditions that enable covalent attachment to substrates like hair and skin that normally lack sufficient reactive functional groups
Solution Approach 2:
The photocatalyst serves as an intermediary that mediates between the non-reactive substrate surface and the active material. By generating acid or base upon light exposure, it creates the necessary chemical environment for covalent bonding to occur on substrates that would otherwise be unreactive
3Duration of action of stationary object
If existing covalent attachment methods are used, then some surface modification is achieved, but the attachment is not sufficiently durable due to water competition and degradation
Solution Approach 1:
The patent replaces conventional chemical attachment mechanisms with a photocatalytic mechanism. Instead of relying on direct chemical reactions that compete with water, light-induced photocatalysis generates acid/base in situ to drive covalent bonding, achieving more stable and durable attachment that resists water degradation
Solution Approach 2:
The photocatalyst is positioned on the substrate surface and activated by light to perform covalent attachment preliminarily before water can cause degradation. This preliminary covalent bonding ensures long-lasting durability by establishing stable chemical bonds that withstand subsequent water exposure
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 enables durable and stable covalent attachment of active materials to substrates, providing long-lasting benefits such as improved texture, reduced dryness, and protection against mechanical and environmental damage, while being physiologically acceptable and compliant with safety regulations.
Implementation Method 1
a photocatalyst capable of generating an acid or a base upon exposure to light
Data Source
AI summary
The present invention includes compositions comprising an active material having groups capable of covalent attachment to a substrate in the presence of an acid or a base, a photocatalyst capable of generating an acid or a base upon exposure to light, and a vehicle. Also included herein is a method for treating a substrate with these compositions. The method includes the steps of applying at least one active material having functional groups to the substrate, applying a photocatalyst to the substrate, and exposing the photocatalyst and the at least one active material to light for forming covalent attachments between the functional groups and constituent groups on the substrate. The compositions and methods described herein are useful in consumer care and personal care product applications.