#polydimethylsiloxane

Polymer 'bristles' could help repel proteins—and germs—from surfaces in medical settings

A non-toxic coating developed by researchers at University of Toronto Engineering prevents proteins from sticking to surfaces—potentially offering a new tool in the fight against hospital-acquired infections. "Right now, the simplest way to keep a surface clean and free of disease-causing microbes is to wash it with disinfectants like bleach," says Professor Kevin Golovin, who heads the Durable Repellent Engineered Advanced Materials (DREAM) Laboratory at University of Toronto Engineering. "But of course, it's not great for the humans that work in these environments to be constantly exposed to these toxic products. And any time you're using chemicals to kill pathogens, you're increasing the chance of some strain evolving to be immune to them."

Researchers create safer nonstick surface, cutting use of 'forever chemicals'

A new material developed by researchers from University of Toronto Engineering could offer a safer alternative to the nonstick chemicals commonly used in cookware and other applications. The new substance repels both water and grease about as well as standard nonstick coatings—but it contains much lower amounts of per- and polyfluoroalkyl substances (PFAS), a family of chemicals that have raised environmental and health concerns. "The research community has been trying to develop safer alternatives to PFAS for a long time," says Professor Kevin Golovin, who heads the Durable Repellent Engineered Advanced Materials (DREAM) Laboratory at U of T Engineering.

Static electricity depends on materials' contact history, physicists show

For centuries, static electricity has been the subject of intrigue and scientific investigation. Now, researchers from the Waitukaitis group at the Institute of Science and Technology Austria (ISTA) have uncovered a vital clue to this enduring mystery: the contact history of materials controls how they exchange charge. The findings, published in Nature, explain the prevailing unpredictability of contact electrification, unveiling order from what has long been considered chaos. From a tiny electric jolt when touching a doorknob to styrofoam peanuts that cling to a mischievous cat's fur—the well-known and seemingly simple phenomenon of static electricity has puzzled people since antiquity. How could this ubiquitous effect, frequently demonstrated to bedazzled children by rubbing a balloon on their hair, still not be completely understood by scientists?

Efficient self-assembly enhances self-healing in advanced siloxane materials

Polysiloxane materials, such as polydimethylsiloxane (PDMS)-based elastomers, exhibit a self-healing capability by the introduction of silanolate (Si–O–) groups. This ability stems from their dynamic siloxane (Si–O–Si) bonds, which can break and reform to repair damage. Their self-healing properties could make them valuable in applications like protective coatings for use in various fields, such as optics, electronics, and aerospace. To improve the properties of PDMS-based materials, they have been combined with inorganic fillers such as nanoparticles or nanosheets. Generally, the introduction of nanosheets into polymers leads to the formation of a layered structure that exhibits superior thermal, mechanical, and gas barrier properties. Furthermore, an improved crack-healing ability of oriented films has been reported. This improvement is attributed to polymer diffusion concentrated in the in-plane direction.

Chip-free wireless sensors could reduce environmental impact of electronic tags

A more sustainable new form of electronic tag could help reduce the vast environmental impact caused by single-use RFID technologies, researchers say. Engineers from the University of Glasgow have developed the new wireless tag system, which can identify objects and measure temperature without the use of microchips. Instead, the tags use inexpensive coils and a sensing material made from a form of silicon rubber called PDMS and carbon fibers. The coils, smaller than the ones found in credit cards, absorb electromagnetic signals from a hand-held reader using electromagnetic waves. The researchers say their new, less wasteful tags could help reduce the retail sector's reliance on RFID chips, which uses more than 10 billion tags each year. Most tags are used just once, and end up in a landfill without appropriate recycling of the electronics.

Silicone Recycling

While consumer silicone products are often selected to replace single-use plastics, reducing the amount of waste generated overall, they too eventually must be disposed of - so what happens to the waste? Although silicone is a polymer, it has a silicon, oxygen based backbone, not carbon based like most polymers and plastics known. As such, silicone will often find its way into landfills when recycled by consumers, as it cannot be recycled with the other polymers in the stream. Silicone is not biodegradable, and takes a considerable length of time to break down.

Silicone can be recycled at designated recycling centers, though typically through mechanical means, resulting in a 'downcycled' product. Apart from consumer recycling, overall recycling rates of silicone is expected to steadily increase over the coming decade.

Researchers develop non-contact touch sensors for robotics

A radical new type of touch sensor for robotics and other bio-mimicking (bionic) applications is so sensitive it works even without direct contact between the sensor and the objects being detected. It senses interference in the electric field between an object and the sensor, at up to 100 millimeters from the object. The researchers at Qingdao University in China, with collaborators elsewhere in China and South Korea, describe their innovation in the journal Science and Technology of Advanced Materials. Electronic skins have become a crucial element in bionic robots, allowing them to detect and react to external stimuli promptly. This can allow robotic systems to analyze an object's shape, and, if required, also to pick it up and manipulate it.

New 3D printing technique integrates electronics into microchannels to create flexible, stretchable microfluidic devices

The transition from traditional 2D to 3D microfluidic structures is a significant advancement in microfluidics, offering benefits in scientific and industrial applications. These 3D systems improve throughput through parallel operation, and soft elastomeric networks, when filled with conductive materials like liquid metal, allowing for the integration of microfluidics and electronics. However, traditional methods such as soft lithography fabrication which requires cleanroom facilities have limitations in achieving fully automated 3D interconnected microchannels. The manual procedures involved in these methods, including polydimethylsiloxane (PDMS) molding and layer-to-layer alignment, hinder the automation potential of microfluidic device production. 3D printing is a promising alternative to traditional microfluidic fabrication methods. Photopolymerization techniques like stereolithography apparatus (SLA) and digital light processing (DLP) enable the creation of complex microchannels.