Shape Memory Polymer Temperature Sensing Strips

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Solution Overview

Problem

Existing temperature sensing devices are often expensive, prone to breaking, require power sources, or are single-use and lack durability, limiting their portability and reversibility.

Innovation Solution

The use of shape memory polymers (SMPs) in temperature sensing devices that undergo a change in modulus of elasticity at a thermal transition temperature, allowing for reversible and reusable temperature measurement through changes in stiffness and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional temperature sensing devices (bulb thermometers, electronic thermometers, pyrometers) are used, then temperature measurement function is achieved, but they are prone to breaking, require power sources, or are single-use

Engineering Contradiction:

Improvedevice durabilityVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the change in modulus of elasticity of shape memory polymer at thermal transition temperature to create temperature sensing strips. The polymer's physical property change (from rigid to flexible) provides a reliable, passive temperature indication without requiring complex electronic components or power sources, thereby improving reliability while reducing device complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs phase transition of shape memory polymer at specific thermal transition temperatures to enable reversible temperature sensing. The polymer undergoes phase change from glassy (rigid) to rubbery (flexible) state, providing durable and repeatable temperature measurement capability without degradation over multiple uses

Inventive Principle:

Principle #36Phase transitions

2Ease of operation

If TLC temperature strips are used, then portability and low cost are achieved, but many are irreversible or designed to be used only once and then discarded

Engineering Contradiction:

ImproveportabilityVSAvoidreusability

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent creates reversible temperature sensing strips using shape memory polymer that can be reused multiple times. The polymer recovers its original shape and mechanical properties after each temperature cycle, eliminating the need to discard the strips after single use and enabling prolonged duration of action

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent uses composite material structure with shape memory polymer embedded in a flexible matrix. This composite construction provides both the temperature-sensing capability and mechanical flexibility needed for portable use, while the shape memory component ensures reversibility and reusability across multiple temperature cycles

Inventive Principle:

Principle #40Composite materials

3Duration of action of stationary object

If some TLC temperature strips are reversible, then reusability is improved, but they suffer from less pronounced color changes with repeated use

Engineering Contradiction:

ImprovereusabilityVSAvoidcolor change visibility

Core Design Contradiction:

Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The patent replaces the optical/color-based detection mechanism of traditional TLC strips with a mechanical detection method. Instead of observing color changes, users feel the change in flexibility and stiffness of the polymer strip, which provides equally pronounced and reliable feedback that does not degrade with repeated use

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 SMP-based temperature sensing devices are cost-effective, portable, and durable, enabling accurate and repeated temperature measurements without the need for power sources, while being environmentally friendly and versatile for various applications.

Implementation Method 1

each of the two or more strips comprises a shape memory polymer adapted to undergo a change in a modulus of elasticity at a thermal transition temperature

Methodology Applied

Scientific EffectShape memory polymer effect: Shape Memory Polymer

Implementation Method 2

the change in the modulus of elasticity of the shape memory polymer results in a change in stiffness and/or flexibility of the stirrer, and wherein the thermal transition temperature is attained by immersing or contacting the stirrer with a fluid

Methodology Applied

Scientific EffectThermal transition: Phase Change

Data Source

PatentUS7628116B2Shape memory polymer temperature sensing devices and methods of use

Publication Date: 2009.12.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A temperature sensing device includes two or more strips, wherein each of the two or more strips comprises a shape memory polymer adapted to undergo a change in a modulus of elasticity at a thermal transition temperature. A method comprises contacting two or more strips with an item, wherein each strip comprises a shape memory polymer adapted to undergo a change in a modulus of elasticity at a thermal transition temperature; equilibrating the two or more strips with the item; and determining a temperature range of the item by observing whether any of the two or more strips underwent a decrease in stiffness and/or increase in flexibility caused by the change in the modulus of elasticity of the shape memory polymer.