The science of adhesives is about how things “Stick Together” and it operates on obvious physical levels as well as (more importantly) molecular levels. So why do things stick together (or fall apart)? It’s all about forces, let’s dive in.
The Science of Adhesives Part 1
(What they are and what they do – and HOW!)
I’ve heard it said that the “Forces” are all around us. (it’s true)
Forces make things stick and mighty molecular bonds are ultimately what it’s all about.
As one veers close to the cutting edge of today’s industrial science of adhesives it really is work done on molecular scale. The science is about a perfect balance of adhesion and cohesion with materials that bond together and to other materials. The right balance of flex to tensile rigidity. There are many other factors which impact adhesion such as temperature, exposure to other chemicals and conditions.
Adhesive science is simple yet complex. In the simplest sense it’s about “sticking things together with sticky stuff” but in the most complex it’s about perfectly coordinated chemical reactions that create the most permanent bonds possible between materials often considered inert. We will cover the science behind Glass Adhesion in the more advanced section of Sealant U. Let’s begin with the foundations on why things stick together (and when not).
About Adhesion
There are numerous different ways molecular bonds create forces that essentially stick things together. Adhesives are substances that create or amplify adhesion. Understanding adhesives means first understanding adhesion.
Adhesion is, in the simplest sense, when things stick together. They “adhere” to each other.
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Adhere: I like to think of it in the sense of “Add Here”! when you add more here, both elements are in the same “here” alas, bonded together or adhered.
Adhesion is based on the push and pull of various natural forces including (not limited to): Gravity, Suction, Friction, Magnetic, Static Adhesion, Cohesive forces, Anchoring and a nearly infinite collection of other bonds and hybrids.
We adhere to the Earth largely due to a force we call gravity which pulls objects together based on their mass. We can break that bond for a moment by jumping or longer by flying in an airplane. These are forces which act upon forces generated by the big “metal magnet ball” we’re spinning on and “adhered” to.
Of course, if your feet were in a 2” (6cm) deep honey, tree sap or tar, you’d have other forces adhering you to the planet and jumping would be more difficult to do. The forces of adhesion vary tremendously based on surface porosity, surface detail and a myriad of other factors.
Usually when we think of adhesives, of course we’re thinking of manufactured glue. Often these are considered by science to be “Adhesive Resins” or “Artificial Resins”. That name stems from the tree sap resins which have been used as adhesives by humans for millennia (and mother nature far longer than that.)
(Soon) The story of love and molecules…
