Rice team modifies laser-induced graphene process to create micron-scale patterns in photoresist

A Rice University team has modified its laser-induced graphene technique to make high-resolution, micron-scale patterns of the conductive material for consumer electronics and other applications. Laser-induced graphene (LIG), introduced in 2014 by Rice chemist James Tour, involves burning away everything except carbon from polymers or other materials, leaving the carbon atoms to reconfigure themselves into films of characteristic hexagonal graphene. The process employs a commercial laser that “writes” graphene patterns into surfaces that to date have included wood, paper and even food.

Rice lab uses laser-induced graphene process to create micron-scale patterns in photoresist image

The new version writes fine patterns of graphene into photoresist polymers, light-sensitive materials used in photolithography and photoengraving. Baking the film increases its carbon content, and subsequent lasing solidifies the robust graphene pattern, after which unlased photoresist is washed away.

"Flash Graphene" process modified to produce graphene from rubber waste

The “flash” process, introduced by Tour and his colleagues at Rice University in 2020, has now been optimized to convert waste from rubber tires into graphene that can, in turn, be used to strengthen concrete.

Rice scientists optimized a process to turn rubber from discarded tires into turbostratic flash graphene image

The atoms reassemble into valuable turbostratic graphene, which has misaligned layers that are more soluble than graphene produced via exfoliation from graphite. That makes it easier to use in composite materials.

Rice team turns pyrolyzed ash into graphene

Researchers at Jamed Tour's lab at Rice University have developed a new process, able to convert worthless pyrolyzed plastic ash into graphene. The technique produces turbostratic graphene flakes that can be directly added to other substances like films of polyvinyl alcohol (PVA) that better resist water in packaging and cement paste and concrete, dramatically increasing their compressive strength.

Converting plastic waste pyrolysis ash into flash graphene image

Similarly to the flash graphene process the Tour lab introduced before, pyrolyzed ash turns into turbostratic graphene. That has weaker attractive interactions between the flakes, making it easier to mix them into solutions.

Rice University scientists modify "flash graphene" technique with a special focus on plastic

Rice University's process to produce pristine graphene in bulk from waste (dubbed “flash graphene”) was recently modified for recycling plastic. Instead of raising the temperature of a carbon source with direct current, as in the original process, the lab first exposes plastic waste to around eight seconds of high-intensity alternating current, followed by the DC jolt.

Flash graphene made from plastic by a Rice University lab imagePost-consumer plastic received from a recycler is then mixed with carbon black and processed into turbostratic graphene via timed pulses of AC and DC electricity. Image by the Tour Group

The products are high-quality turbostratic graphene, a valuable and soluble substance that can be used to enhance electronics, composites, concrete and other materials, and carbon oligomers, molecules that can be vented away from the graphene for use in other applications.