Block Copolymer Composition for Stretchable Crack-Resistant Conductors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conductive substances and pressure-sensitive adhesive materials used in healthcare devices, wearable devices, and robotics often experience cracks and peeling due to structural destruction from repeated stretching, especially when used on curved or movable parts.
Innovation Solution
A block copolymer with a triblock or star-shaped structure, composed of ethylenically unsaturated monomers, featuring specific glass transition temperatures and mercapto groups, is developed through living radical polymerization, enhancing stretchability and reducing crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive substances or pressure-sensitive adhesive materials are used, then conductivity or adhesiveness is achieved, but cracks occur due to structural destruction from repeated stretching
Solution Approach 1:
The patent changes the molecular structure parameters by using a block copolymer with specific glass transition temperatures (TgA ≥ 20°C, TgB < 20°C) and controlled molecular weight (Mn: 5,000-500,000). This parameter optimization allows the material to maintain structural integrity while achieving excellent stretchability and crack resistance through the dual-phase structure.
Solution Approach 2:
The invention creates a composite material system by combining two distinct polymer blocks (A and B) with different Tg characteristics into a block copolymer. This composite structure at the molecular level provides both the strength needed to prevent cracking and the flexibility required for repeated stretching without structural destruction.
2Reliability
If conductive material is added to enhance conductivity, then electrical conduction is improved, but the conductive material peels off during extension and voids are generated
Solution Approach 1:
The patent optimizes the molecular weight parameter (Mn: 5,000-500,000) and glass transition temperature parameters of the block copolymer to enhance the matrix's ability to bond with conductive materials. The specific Tg range creates an optimal balance between adhesion and flexibility, preventing conductive material peeling while maintaining structural integrity during extension.
Solution Approach 2:
The block copolymer acts as an intermediary material between the conductive particles and the substrate. Its dual-phase structure with specific Tg characteristics provides both adhesion to the conductive material and flexibility to accommodate stretching, preventing void formation and peeling while maintaining electrical conductivity.
3Adaptability or versatility
If pressure-sensitive adhesive material is stretched, then conformability to curved parts is achieved, but the material peels off from the adherend
Solution Approach 1:
The patent carefully controls the glass transition temperature parameters of the block copolymer (TgA ≥ 20°C, TgB < 20°C) to optimize the balance between adhesion and elasticity. This parameter optimization enables the adhesive to conform to curved surfaces while maintaining sufficient bonding strength to prevent peeling during stretching.
Solution Approach 2:
The block copolymer's composite structure combining hard segments (block A with higher Tg) and soft segments (block B with lower Tg) provides both the adhesion needed for strong bonding and the elasticity required for conformability to curved surfaces without peeling during deformation.
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 block copolymer effectively reduces crack occurrence during extension, providing excellent stretchability and self-pressure-sensitive adhesiveness, suitable for use in stretch conductors and pressure-sensitive adhesive films.
Implementation Method 1
A block copolymer mainly composed of a structural unit derived from an ethylenically unsaturated monomer, which has at least one mercapto group, a number average molecular weight of 5,000 to 500,000, and a block structure that is a triblock structure of polymer block (A)-polymer block (B)-polymer block (A) or a star-shaped block structure
Implementation Method 2
the glass transition temperature of the polymer block (A) is 20° C. or higher, and the glass transition temperature of the polymer block (B) in the case of the triblock structure and the glass transition temperature of [polymer block (B)]qX in the case of the star-shaped block structure are lower than 20° C.
Data Source
AI summary
A block copolymer consists mainly of structural units each derived from an ethylenically unsaturated monomer and has at least one mercapto group. The block copolymer has an Mn of 5,000-500,000 and has a block structure, which is an A-B-A triblock structure or a star-shaped block structure of [A-B]qX. The q is an integer of 2-6. The polymer block (A) has a glass transition temperature of 20° C. or higher. The polymer block (B) of the triblock structure has a glass transition temperature lower than 20° C., and the [polymer block (B)]qX of the star-shaped block structure has a glass transition temperature lower than 20° C. The X is an initiator residue or/and a coupling-agent residue or is a derivative thereof.