Shape Memory Elastomeric Composite for Reversible Adhesion

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Solution Overview

Problem

Conventional shape memory polymers used in reversible adhesives are relatively rigid, limiting their application to only planar surfaces, as they require a switching mechanism to lock in a temporary shape, making them unsuitable for curved or textured surfaces.

Innovation Solution

A soft elastomeric composite with temperature-controlled shape memory and reversible adhesive properties is developed, comprising poly(ε-caprolactone) fibers and polyhedral oligomeric silsesquioxane-containing thermoplastic polyurethane elastomer fibers, which are dispersed and intertwined, allowing for high strain and conformability to irregular surfaces, and can be controlled to bond and debond through temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional shape memory polymers are used in reversible adhesives, then the adhesive can switch between adhesive and non-adhesive states, but the adhesive is relatively rigid and can only be used on planar surfaces

Engineering Contradiction:

Improveapplicability to different surfacesVSAvoidrigidity

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent uses a composite material consisting of shape memory polymer fibers embedded in an elastomeric matrix. This combination allows the adhesive to maintain the shape memory switching capability while gaining the flexibility and conformability of the elastomeric material, enabling application on curved and textured surfaces

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The adhesive is formulated as a soft elastomeric material that can conform to irregular surfaces. The elastomeric matrix provides the necessary flexibility and compliance to adhere to curved, textured, and non-planar surfaces while the embedded shape memory fibers provide the switching mechanism

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of operation

If shape memory polymers are used to provide reversible adhesion, then controllable debonding is achieved, but the switching mechanism requires the material to be rigid

Engineering Contradiction:

Improvecontrollable debondingVSAvoidrigidity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The composite structure separates the switching function (performed by rigid shape memory fibers) from the structural function (performed by the soft elastomeric matrix). This allows the material to be soft and conformable while still containing the switching mechanism needed for controllable debonding

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The adhesive is divided into two functional components: shape memory polymer fibers that provide the switching mechanism for controllable debonding, and an elastomeric matrix that provides softness and conformability. Each component performs its specific function independently while working together as a unified adhesive system

Inventive Principle:

Principle #1Segmentation

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 composite mat exhibits over 1000% strain prior to failure, low Young's modulus, and reversible adhesive properties, enabling it to conform and adhere to curved or textured surfaces, with adjustable adhesive strength and easy delamination by exploiting shape memory effects, making it suitable for various applications including home improvement, medical, and manufacturing uses.

Implementation Method 1

the first set of fibers comprise poly(ε-caprolactone) and wherein the second set of fibers comprise a polyhedral oligomeric silsesquioxane-containing thermoplastic polyurethane elastomer. The poly(ε-caprolactone) fibers have a melting point of around 56 degrees Celsius.

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

Conventional reversible adhesives may be made from shape memory polymers, which are polymers with the ability to fix a temporary shape, while memorizing their permanent form. The deformed SMP can indefinitely hold the temporary shape. Activation via an external stimulus, such as heat, light, electricity, or magnetic fields triggers recovery back to the permanent shape.

Methodology Applied

Scientific EffectShape memory polymer effect: Shape Memory Polymer

Implementation Method 3

The invention also comprises the method of providing a reversible adhesive by the steps of providing a composite mat having a first set of fibers and a second set of fibers that are dispersed and intertwined together, wherein the first set of fibers comprise poly(ε-caprolactone) and the second set of fibers comprise a polyhedral oligomeric silsesquioxane-containing thermoplastic polyurethane elastomer. The preliminary step of simultaneously electrospinning the first set of fibers with the second set of fibers to make the composite mat of dispersed and intertwined fibers.

Methodology Applied

Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentUS10081746B2Conformable reversible adhesives with shape memory assisted delamination

Publication Date: 2018.09.25 SYRACUSE UNIVERSITY

AI summary

A shape memory elastomeric composite that has temperature-controlled, shape memory, and reversible adhesive properties, and is soft enough to confirm to an irregular surface. The composite is formed from a synthesized polyhedral oligomeric silsesquioxane-containing thermoplastic polyurethane elastomer and poly(ε-caprolactone) by electrospinning the two components separately and simultaneously and then hot compacting the electrospun composition to form a dense film.