University Physics Professor creates new, comfortable earplug

Lou Bloomfield designs shape memory material to aid ear protection

hs-earjellies-CourtesyRudy McEntire

In Bloomfield’s shape memory material, the silicon material consists of temporary cross-links. This allows the material to mold to the shape of a person’s ear more easily, making the earbuds customized to each owner.

Courtesy Rudy McEntire

University Physics Prof. Lou Bloomfield has created a new shape memory material, MemorySil, to construct comfortable earbuds. Drawing inspiration from Silly Putty, Bloomfield looked to make a material that would be adaptive and moldable on a long-time scale, but firm and solid-like on a short-time scale. 

“Imagine a rubber that is so soft that it’s own weight smushes it, but it doesn’t seem soft when you poke at it,” Bloomfield said. “It has a layer of shape memory on the top, whatever shape it is currently in, it will defend almost to the death.”

Entrepreneur Rudy McEntire recently moved from a quiet area in Colorado to San Francisco and would routinely wear foam earplugs on his commutes. Due to the discomfort he experienced daily, he decided to seek out material to make his own earplugs and contacted Bloomfield after finding his work with shape memory material online. After making several prototypes, Bloomfield eventually found a consistency that he believed would be most adaptable to people’s ears. 

“EarJellies work by slowly and gently expanding in the ear canal to create a soft seal … EarJellies will not fall out the same way foam earplugs will, too,” McEntire said in an email to the Cavalier Daily. 

The material that Bloomfield created is a silicon rubber modelled after Silly Putty. He found that Silly Putty is made of polymer chains linked together by cross-links, chemical bonds. Most rubbers require very low temperatures for the cross-links to hinder fluidity, making them very mobile materials. 

Most rubbers consist of permanent cross-links. However, in Bloomfield’s shape memory material, the silicon material consists of temporary cross-links. This allows the material to mold to the shape of a person’s ear more easily, making the earbuds customized to each owner.

“They are perpetually changing partners with the polymer chains so when you pull it flows,” Bloomfield said. “What you are seeing is the network evolving.”

McEntire says that EarJellies also prove to be reusable, making them more environmentally friendly than the commercial foam earplugs that may appear to be cheaper. 

Bloomfield and McEntire hope that their product will benefit groups such as swimmers, light sleepers and individuals with chronic ear injuries. The EarJellies have been found to protect users from around 25 decibels of sound and can also be worn to protect the ears at loud sporting events or at rock concerts, which often leave individuals with ringing ears and permanent ear damage. 

In the next few weeks, EarJellies will be featured in a campaign on Kickstarter, a company that works as a funding platform for new creative products. Individuals can find companies like EarJellies on Kickstarter and become backers of the company. In exchange, companies send their materials to their backers first. 

EarJellies will ship to these backers around April. Bloomfield hopes that EarJellies will be able to be sold on online websites such as Amazon by this summer and include five different sizes to fit various ear types and sizes. 

Although they are sticking to earbuds for now, Bloomfield hopes that in the future his shape memory material can be used in a variety of other items such as shoes, crutches, eyeglasses, bicycle seats and even on prosthetic limbs to provide comfort. 

“The value of this whole operation with Rudy has been not just the earplugs, but to do something of value that makes the world a better place,” Bloomfield said. 

related stories