Shulou(Shulou.com)11/24 Report--

Post-it notes are one of the most commonly used items in our lives. They are small, easy to stick, and can be torn off without leaving a trace. We often use it as a memo, or to record the spark of thought that pops up in our mind at a certain moment.

Some time ago, I saw such a video on the Internet, saying that the method of tearing up post-it notes is exquisite. If you peel from the bottom up, you'll end up with a curled sticky note that won't stick and won't take long to come off.

Tear it from the bottom up and the sticky note "rolls up" but if you tear it from the side along the glue, you get a flat sticky note that sticks well and doesn't fall off for a long time.

Tear from the side, sticky note "lying flat" as a small editor of physics, exploring the principle behind the phenomenon is our daily operation. There must be a variety of reasons behind different tearing methods to bring different shapes of post-it notes.

So today we will dig a good dig, this day and night with us to get along with the post-it, what are the unknown stories.

Part.1 Great invention comes from two accidents When it comes to the birth of post-it notes, we have to mention two accidents. Speaking of these two accidents, we naturally have to talk about two scientists_Spencer F. Dr Silver and Dr Arthur Fry.

Spencer F. Silver received his Ph.D. in organic chemistry from the University of Colorado at Boulder in 1966 and began working on a stronger binder for aircraft manufacturing.

Spencer F. Silver |Source: cen.acs.org In 1968, Dr. Silver was adding a chemical reagent that could polymerize molecules to the reactants in an experiment, but this time accidentally put more, resulting in a novel experimental phenomenon-particles that should have been dissolved in the solvent did not dissolve, but dispersed in the solvent.

This phenomenon aroused his interest, and after further experiments, he prepared an adhesive with high viscosity but easy to peel, and it could be pasted repeatedly after peeling.

However, because this binder is far from the original goal, the company did not pay attention to it. But Dr Silver always believed there was a use for the adhesive, so he introduced it to everyone. Hard work pays off, finally waiting for another intelligent brain.

That's right, that intelligent brain is Dr. Arthur Fry. Dr. Fry, a member of the choir, often needed to record hymns on paper, but the paper always fell out of the book or slid between pages, so he thought it would be nice if he could make the paper stick firmly in the book.

Arthur Fry |Source: wikipedia Once while singing, he thought of Dr. Silver's previous report, and immediately found Dr. Silver to borrow some samples of adhesive and spread them on paper.

This is the original form of post-it notes. Later, Dr. Fry further optimized the manufacturing process of the adhesive on the basis of Dr. Silver, so that after the adhesive was attached to the paper, even after repeated pasting and peeling, no traces were left, and the adhesive force did not change significantly.

How did the post-it notes become marketable? It actually comes from a shift in perspective.

At first Dr Fry used the adhesive strips as bookmarks, but once he discovered that they could also be used as communication tools. Sticking a piece of paper to a document and handing it to someone else allows you to express your thoughts in the same way when you can't see them, and the other person can respond in the same way.

This made Dr. Fry's eyes light up. This was not a simple bookmark, but a note! When such an idea is deeply rooted in the hearts of the people, the use of notes has greatly increased, and gradually entered the lives of more people.

In fact, many great discoveries and inventions in history originated from some accidents, but these accidental occurrences all came through long-term efforts and accumulation. Any success will not be achieved overnight, but should be down-to-earth and forge ahead.

Part.2 Who controls the in-roll behavior of Post-it notes? As the saying goes, the structure determines the nature, that is to say, the molecular structure of the adhesive determines the behavior of the final layer of pressure sensitive adhesive under the action of external force.

Dr. Silver was the first to invent "low-tack" adhesives made from tiny acrylic acids. The following diagram shows the structural formula of some monomers that meet manufacturing standards:

Source: References [4] The materials used to make pressure-sensitive adhesives are now more diverse, and there are more choices on the basis of satisfying functionality and safety.

So why does different tearing method bring different appearance of sticky notes? It simply has to do with the force we exert.

When we apply force to the sticky note, the paper itself will deform, and due to the viscosity of the pressure sensitive adhesive, it is easier to maintain the deformed appearance.

When tearing from the bottom up, we equivalent to tearing the long side of the pressure sensitive adhesive, so it will curl the entire edge; and when tearing from the side, we equivalent to tearing the short side of the pressure sensitive adhesive, although the same will curl, but because the width is small, and the part without pressure sensitive adhesive will limit the degree of curling, and finally it will appear very flat.

Of course, this is only a very simple qualitative description, the more essential reason is due to the interaction between the components of the pressure-sensitive adhesive molecules, and irreversible deformation occurred under the action of stress, some specific quantitative relations will not be detailed here.

Part.3 Conclusion Therefore, although sticky notes are commonly used tools in our daily life, we know very little about them, and their hidden knowledge points are beyond our imagination.

At the same time, when I saw that the post-it note with "inner volume" in the cover picture had fallen off the wall, Xiao Bian also instantly understood that only "refuse inner volume" can we fight for a long time...

resources

[1] Fry A. The post-it note: An intrapreneurial success[J]. SAM Advanced Management Journal, 1987, 52(3): 4.

[2] Arthur Fry - Wikipedia

[3] Spencer Silver - Wikipedia

[4] Silver S F. Acrylate copolymer microspheres: U.S. Patent 3,691,140[P]. 1972-9-12.

Some pictures come from the Internet

This article comes from Weixin Official Accounts: Institute of Physics, Chinese Academy of Sciences (ID: cas-iop), edited by Eric

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