Flexible Strain Sensor Using Aerosol-Jet CNT-Metal Nanoparticle Printing
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Solution Overview
Problem
Conventional strain sensor manufacturing techniques face challenges in achieving both high sensitivity and a wide measurable range while maintaining durability, as they often require chemical post-treatment and heat processes, and the bonding between conductive lines and substrates is not secure enough to withstand frequent deformation.
Innovation Solution
A method involving direct printing of a mixture of metal nanoparticles and carbon nanotubes (CNTs) onto a flexible substrate using a high-speed aerosolized process without liquid organic solvents, creating a mechanical locking structure that enhances durability and eliminates the need for chemical post-treatment and heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional inkjet printing method is used to print conductive lines, then the manufacturing process can be simplified, but the bonding between conductive lines and substrate is weak and cannot withstand frequent deformation
Solution Approach 1:
The patent replaces the conventional chemical bonding mechanism (using organic solvents and chemical post-treatment) with a mechanical bonding mechanism. The liquid ink penetrates into the porous substrate structure and forms mechanical interlocking, eliminating the need for chemical post-treatment processes while achieving strong, durable bonding that withstands frequent deformation.
Solution Approach 2:
The patent utilizes the porous structure of the substrate to enable liquid ink penetration. The pores allow the ink to infiltrate deep into the substrate, creating extensive mechanical interlocking surfaces. This porous material approach provides strong bonding without requiring additional chemical treatment steps.
2Ease of operation
If liquid ink with organic solvent is used for printing, then the conductive line can be applied to substrate surface, but chemical post-treatment and heat treatment are required and bonding is not secure
Solution Approach 1:
The patent extracts and removes the organic solvent component from the ink formulation, using only water as the carrier. This extraction eliminates the need for chemical post-treatment processes that would otherwise be required to remove or neutralize organic solvents, simplifying the overall manufacturing process while maintaining effective bonding.
Solution Approach 2:
The patent employs a self-drying mechanism where the water-based ink naturally evaporates the water carrier without requiring external heat treatment. The ink formulation and substrate combination allows for spontaneous drying and bonding, eliminating the need for separate heat treatment processes.
3Adaptability or versatility
If the substrate undergoes frequent deformation, then the sensor can measure dynamic changes, but the bonding between conductive line and substrate deteriorates
Solution Approach 1:
The patent creates a dynamic bonding structure where the liquid ink can penetrate and adapt to the substrate's porous structure, forming a flexible mechanical interlock. This dynamic bonding mechanism maintains strong adhesion even when the substrate undergoes frequent or large deformations, as the mechanical interlocking structure can accommodate dimensional changes without breaking the bond.
4Measurement precision
If high sensitivity is achieved through conventional methods, then the sensor can detect minute deformation, but the measurable range is limited and durability is compromised
Solution Approach 1:
The patent uses a composite approach combining water-based liquid ink with conductive particles to create a conductive line material that provides both high sensitivity for minute deformation detection and the mechanical robustness needed for large deformation measurement. The water-based formulation ensures strong bonding while the conductive particles maintain electrical properties across a wide range of deformations.
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 method results in a strain sensor with excellent sensitivity, a wide measurable range, and long-term durability, as the CNTs penetrate into the substrate, maintaining a strong bond with the conductive lines, allowing accurate deformation measurement even under large deformation conditions.
Implementation Method 1
jetting aerodynamically a powdery printing material mixture containing only metal nanoparticles and CNTs in an aerosolized state
Implementation Method 2
jetted out through the nozzle toward a surface of the flexible substrate by a compression wave caused by a pressure difference
Data Source
AI summary
Disclosed are a flexible strain sensor and a method for manufacturing the same. A conductive line pattern is directly printed on a flexible substrate by jetting a printing material mixture of metal nanoparticles and CNTs at a high impact speed, and sandwiched between the flexible substrate and a flexible cover. The mixture is excited by aerodynamically controlling pumping timing and jetted onto the flexible substrate in an aerosolized state through a nozzle. The jetted mixture collides with the surface of the flexible substrate to create cracks, and then CNTs penetrate into the cracks and are mechanically locked with the flexible substrate. Subsequently, metal nanoparticles and CNTs are deposited thereon to a predetermined width and height, forming the conductive line pattern. This direct printing can be performed in a low pressure and at room temperature without using solvents or resins, thus no need for additional chemical post-treatment or heat treatment.