UV-Curable Debondable Adhesive for Repairable Electronics
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Solution Overview
Problem
Existing adhesives used in electronic devices lack the ability to maintain strong adhesion under traumatic conditions and are not easily removable for recycling or repair, posing challenges in device longevity and component reuse.
Innovation Solution
A curable composition comprising a film-forming polymeric material, epoxy resin, and ionic liquid, which can be cured with UV radiation and debonded using a direct current electric potential, providing structural adhesion and recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If conventional adhesives are used to bond components in electronic devices, then adhesion strength is achieved, but the adhesives cannot be easily removed for recycling or repair
Solution Approach 1:
The adhesive composition transitions from a permanently bonded state to a debonded state through application of an external electric field. The ionic liquid components enable dynamic reversibility of the adhesive bond, allowing the material to switch between strongly adhering and easily separable states based on electrical stimulation.
Solution Approach 2:
The adhesive properties are changed by applying an electrical parameter (voltage or current). The ionic liquid constituents respond to electrical fields by altering their distribution and interaction with substrate surfaces, thereby changing the adhesive strength from high to low without thermal or mechanical processing.
2Strength
If strong adhesives are used to maintain adhesion under traumatic forces, then impact resistance is improved, but component separation for recycling becomes difficult
Solution Approach 1:
The ionic liquid acts as an intermediary mechanism between the adhesive matrix and substrate surfaces. Under normal conditions, it provides strong adhesion through electrostatic and chemical interactions. Under electrical stimulation, it mediates the separation process by reducing these interactions, enabling clean component separation without damage.
Solution Approach 2:
The separation mechanism replaces traditional mechanical methods (heating, scraping, chemical solvents) with an electrical field application. The ionic liquid responds to the electrical stimulus to facilitate bond breakdown, substituting mechanical separation processes with a controlled electrical debonding approach.
3Duration of action of stationary object
If permanent adhesives are used for structural bonding, then device durability is enhanced, but adhesive removal for component reuse is not feasible
Solution Approach 1:
The adhesive system provides self-service functionality by enabling its own removal through application of an external electric field. The ionic liquid components inherently possess the capability to reverse the bonding process when stimulated electrically, eliminating the need for external chemical or mechanical removal processes.
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 composition offers impact resistance, structural adhesion, and enables easy separation of components for reuse or recycling, enhancing device durability and sustainability.
Implementation Method 1
exposing the layer of the curable composition to ultraviolet radiation... curing the curable layer to bond the first substrate to the second substrate
Implementation Method 2
an ionic liquid that has a melting point less than 100 degrees Celsius and that has an anion selected from SbF6−, PF6−, or a mixture thereof... applying a direct current electric potential across the cured composition to separate the first substrate from the second substrate
Data Source
AI summary
Curable and cured compositions as well as articles containing the curable or cured compositions are provided. The cured compositions are typically a semi-structural or structural adhesive. Advantageously, the cured compositions can be removed (e.g., de-bonded) from the various surfaces of the articles after the useful lifetime of the articles, to correct misplacement of a part during manufacturing, or to repair the electronic device. The separation step occurs using a direct current electric potential across the cured composition.