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Pressure Sensitive Adhesives that are Smart and Switchable

Edward M. Petrie – Jul 25, 2018

Pressure Sensitive Adhesives that are Smart and SwitchableMaterials seem to be getting more intelligent, and adhesives are no exception. Not only do adhesives perform their primary function of providing an adequate bond between substrates, they can now execute numerous additional functions that are becoming increasingly technological and valuable.

Despite the many well-known advantages of conventional adhesives, there is a demand for added value through further functionality, and this often requires a moderate amount of intelligence being integrated into the material.

Certain “smart” adhesives are able to sense the environment and adapt to it in various ways. The innovation and wealth of technology developed in recent years are appropriate for many purposes.

Switchability or going from one state to another is the most notable accomplishment in these intelligent systems. Examples of switchability include:

 − Strong adhesion to fast detachment
 − Insulator to conductor
 − Hydrophobicity to hydrophilicity
 − Rigid to elastic
 − One color to another color, etc.

The table below lists few examples of 'smart' adhesive properties1:

Smart Adhesive Property Applications
Color change
 − Color matching
 − High contrast for visible security
 − Mixing and curing monitoring
Disassembly
 − Debonding on demand
 − Recycling of parts
 − Improved maintenance and servicing capabilities
Thermal and electrical 
conductivity
 − Thermal management in electronics
 − Organic solder replacements
 − EMI/RFI shielding
Vibration absorption
 − Thread locking
 − Vibration damping in transportation
 − Sound deadening
Self-indication
 − UV fluorescence for automated quality control
 − Color change in the presence of hazardous gases, temperatures, etc.
Security
 − Including trace components for authentication
 − Tamper resistant tapes
 − Radio-frequency identification tags


It is important that the adhesive properties of the materials are not sacrificed for the additional switchable function.

One of the most important functions of these new adhesives is the ability to release their bond on command by application of:

 − Temperature
 − Electric or magnetic fields
 − Light
 − pH, and
 − So forth

These systems usually consist of introducing a “switch” mechanism into a strongly adhering adhesive so that its adherence is reduced significantly at the time of removal by the operation of the “switch”.


 » Continue reading to investigate how pressure sensitive adhesives can provide multiple functions such as switchability and the commercial value that can be realized by doing so! 

2 Comments on "Pressure Sensitive Adhesives that are Smart and Switchable"
Edward M. P Aug 30, 2018
Yes Alessandro, you are correct. SBC polymers can be considered "smart and switchable" for the reasons that your suggest. Actually, any polymer that is tied together with "pseudo-crosslinks" (mechanical rather than chemical) could be counted into this category. As the temperature increases the molecules will likely disentangle. An important category here could include interpenetrating polymer networks or IPNs.
Alessandro B Aug 27, 2018
Can the block copolymers (SBS, SIS, SEBS...) be considered "smart materials"? Glassy polystyrene domains build a network providing adhesive and cohesive properties (peel, tack, holding power) to the Hot Melts expecially at room temperatures. But as temperature increases beyond the Polystyrene Tg, the network fails and usually the adhesive material loses its properties (tack, peel).

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