Scientists have discovered the secret to producing the perfect glass – antimicrobial and streak-free

Ideally, window or car glass, as well as the coating of gadget screens, should repel water and not collect harmful microflora. Today, “harmful” chemicals and expensive processes are used to produce such glass. Scientists from the Australian Curtin University (CU) have discovered the secret of an environmentally friendly and fairly simple process for producing conditionally ideal glass, for which a salt bath and ultrasound were enough.

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When creating specialized glass, engineers typically have two options. The first is a process that uses silicification reactions, which bond molecular compounds to the glass surface. The second is coating the glass with polymers. Both of these methods involve toxic chemicals, and in the case of coatings, the glass’s unique properties can fade over time.

The new technology proposed by scientists uses ultrasound to irreversibly change the structure of glass without adding any other chemicals. The result is glass that can completely repel water or acquire a positive electrical charge.

However, it is impossible to do without chemistry at all. But this is a soft chemistry, which is widely used in the production of dyes based on organic compounds. The salt bath, in which the glass is placed to give it unique properties, contains a solution of so-called diazonium salts. Depending on the selected salt, the glass is either water-repellent or acquires a positive charge. Then the bath with the solution and the glass is irradiated with ultrasound at a frequency of 24 kHz, which leads to the formation of small bubbles and microexplosions that change the surface of the glass.

The bubbles in the solution explode, releasing heat and creating pressure on its surface. This binds the molecules from the solution to the molecules of the glass. The coating is maximally integrated and does not become thinner during use. Since the solution is non-aggressive, the production of unique glass will be as clean as possible.

«”Sound waves create microscopic bubbles in a diazonium salt solution, which then rapidly collapse, creating tiny bursts of heat and pressure,” the authors explain. “This triggers a reaction that forms a stable organic layer on the glass, making it either water-repellent or positively charged, depending on the type of diazonium salt used. Unlike conventional coatings that wear off over time, our method creates a chemical bond at the molecular level, making it much more durable and environmentally friendly.”

In addition to self-cleaning properties, the promising glass could play a more important role in fighting germs, increasing biofuel production, or creating more efficient water filtration systems. This is because there are a number of types of bacteria and fungi that are attracted to hydrophobic surfaces. A water-repellent version of the glass has also proven effective in combating E. coli. The glass fibers produced by the new method could be used in filters to remove such microorganisms from tap water.

In addition, the researchers found that hydrophobic glass effectively retained types of baker’s and brewer’s yeast. This means that the material could be used to more effectively and accurately control fermentation processes, which could lead to improved beer flavor.

Finally, there are species of microalgae that are attracted to positively charged surfaces. In particular, a species of microalgae known as C. vulgaris sticks well to charged glass. This means that such glass could be used in the production of biofuels, where the accumulation of this organism would be an important step, as the scientists also reported in an article in the journal Advanced Functional Materials. The main thing is that production would not be complicated, dirty, or expensive.