Helical Optically Active Polypeptide Piezoelectric Substrate
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Solution Overview
Problem
Piezoelectric materials used in sensors and actuators face issues with durability, particularly when subjected to deformation or high-temperature and high-humidity environments, leading to reduced sensitivity and stability, and biodegradability concerns in applications requiring long-term reliability.
Innovation Solution
A piezoelectric substrate with an elongate body helically wound from an optically active polypeptide, such as spider silk protein, which maintains orientation and hydrolysis resistance, ensuring excellent durability and stability even in harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If film-form piezoelectric bodies are used in sensors and actuators, then piezoelectric sensitivity is achieved, but durability is reduced when subjected to deformation or high-temperature and high-humidity environments
Solution Approach 1:
The patent changes the material parameter from conventional piezoelectric ceramics or polymers to optically active polypeptide fibers with specific helical structures. This material substitution enables the piezoelectric body to maintain both high durability and stable piezoelectric sensitivity under deformation and harsh environmental conditions, resolving the contradiction between reliability and composition stability.
Solution Approach 2:
The patent uses composite structures consisting of optically active polypeptide fibers with helical configurations embedded in a matrix material. This composite approach combines the high durability of the polypeptide fiber structure with the piezoelectric properties, achieving both improved reliability and maintained sensitivity under various stress conditions.
2Reliability
If polylactic acid polymer-containing piezoelectric bodies are used, then piezoelectricity is expressed without poling treatment and transparency is maintained, but biodegradability causes concerns for long-term reliability
Solution Approach 1:
The patent changes the polymer material from polylactic acid (which is biodegradable) to optically active polypeptides such as poly(γ-benzyl glutamate) or poly(γ-methyl glutamate). These alternative polypeptide materials provide comparable piezoelectric properties and optical transparency but exhibit superior resistance to biodegradation, thereby ensuring long-term reliability without sacrificing the ease of piezoelectricity expression.
3Reliability
If natural polymers such as cellulose or amylose are used, then optical activities and piezoelectricity occur due to orientation, but durability in harsh environments is reduced
Solution Approach 1:
The patent modifies the chemical structure and physical configuration of the polypeptide materials to create highly oriented helical structures that are inherently more resistant to environmental degradation. By controlling the degree of orientation and helical configuration, the patent achieves both the optical activity needed for piezoelectricity and enhanced durability against harmful environmental factors.
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 substrate exhibits enhanced durability and stability, maintaining piezoelectric sensitivity and resistance to environmental degradation, making it suitable for applications requiring long-term reliability and resistance to deformation.
Implementation Method 1
it is known that polylactic acid polymers are allowed to express piezoelectricity only by a mechanical stretching operation
Implementation Method 2
the use of an optically active polymer, such as a synthetic polypeptide
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Provided is a piezoelectric substrate, containing an elongate piezoelectric body that is helically wound, in which the piezoelectric body includes an optically active polypeptide, a length direction of the piezoelectric body and a main orientation direction of the optically active polypeptide included in the piezoelectric body are substantially parallel to each other, and the piezoelectric body has a degree of orientation F of from 0.50 to less than 1.00, as determined from X-ray diffraction measurement by the following Formula (a): DegreeoforientationF=180°−α/180° in Formula (a), α represents a half width (°) of a peak derived from orientation.