Researchers at RMIT University have developed a nylon-11 film that generates electricity when squeezed, stepped on, or even crushed under the weight of a car, and keeps working afterward. The device, which relies on a technique called electroacoustic processing to align the film’s internal crystal structure, achieved a piezoelectric voltage coefficient that far exceeds prior nylon-based materials. Published in Nature Communications, the peer-reviewed study positions the nylon film as a durable, non-toxic alternative to fluorinated polymers widely used in pressure sensors and energy-harvesting devices, with the authors detailing how the engineered crystal alignment underpins the unusually high voltage output.
How Sound Waves Rearrange Nylon’s Crystal Structure
The core innovation is a processing method known as surface-reflected bulk wave, or SRBW, treatment. Rather than relying on heat or chemical solvents to coax nylon-11 into its piezoelectric form, the RMIT team used high-frequency acoustic energy to align the polymer’s crystalline domains. The result is a thin film whose molecular chains are oriented in a way that efficiently converts mechanical stress into voltage. The technique sidesteps a long-standing barrier in polymer science: nylon’s strong hydrogen bonds, which have historically made it difficult to lock into the ferroelectric crystal phase needed for piezoelectric behavior. This was a challenge that prior researchers had to tackle with elaborate thermal and solvent-based protocols.
Earlier work had shown that the desired ferroelectric phase, called the delta-prime phase, could be induced in nylon-11 through humidity-modulated casting and melt-quenching, with phase confirmation carried out using grazing-incidence wide-angle X-ray scattering and infrared spectroscopy. Foundational research also demonstrated that solution-processed ferroelectric nylon thin films were achievable despite those hydrogen-bonding challenges, pointing to nylon’s latent potential as a piezoelectric polymer even before SRBW was conceived. What the RMIT group added is a scalable, energy-efficient route to the same outcome, one that does not require tightly controlled humidity environments or complex solvent chemistry, and that can in principle be integrated with roll-to-roll manufacturing.
Record Voltage Output and 20,000-Cycle Durability
The numbers behind the film’s performance set it apart from previous nylon ferroelectrics. The team reported a piezoelectric voltage coefficient (g33) of 427 × 10−3 V·m/N, a figure that represents the highest value recorded for this class of material. That coefficient measures how much voltage a material produces per unit of applied force, and a higher number means more electrical output from the same amount of pressure. For context, conventional ceramic piezoelectrics used in industrial sensors typically offer strong charge output but are brittle and rigid, making them unsuitable for wearable or flexible applications, whereas the nylon film combines respectable signal strength with bendability and impact resistance.
Durability testing was equally striking. The nylon-11 films maintained stable performance over 20,000 compression cycles at 50 newtons, showing no measurable degradation in output. First author and RMIT PhD researcher Robert Komljenovic said the films were “flexible, tough and reliable, maintaining their performance,” underscoring that the material can withstand repeated loading without fatigue in the tested range. He added that “this method could power next-generation devices that need to survive real-world stresses, whether that’s wearable tech, sensors, people, machines or vehicles.” The team also subjected the device to repeated car run-overs, and the film continued generating electricity under tonnes of pressure, a demonstration designed to prove its viability in harsh, real-world conditions like roadway sensors, industrial monitoring pads, or structural-health systems embedded in concrete.
Why Ditching Fluoropolymers Matters
The environmental angle gives this research an urgency that goes beyond lab benchmarks. Most commercial piezoelectric and triboelectric energy harvesters rely on fluorinated polymers such as PVDF and PTFE. These materials belong to the broader family of per- and polyfluoroalkyl substances, commonly known as PFAS, which have drawn increasing regulatory scrutiny due to their persistence in the environment and links to health concerns. A 2024 review in the journal Small examined alternatives to fluoropolymers for motion-based energy harvesting, cataloging approaches including piezoelectricity, triboelectricity, ferroelectrets, and flexoelectricity, and identifying non-fluorinated polymers like nylon as promising candidates for devices that need to be both flexible and more environmentally benign.
The RMIT nylon-11 film fits squarely into that gap. Associate Professor Amgad Rezk, a co-author on the study, said the process offered significant advantages for industry, describing it as energy-efficient and scalable, which is crucial if manufacturers are to move away from entrenched PFAS-based materials. That claim carries weight because nylon-11 is already manufactured at industrial volumes for use in tubing, coatings, and automotive parts, meaning the raw material supply chain already exists and is well understood. The challenge has always been processing it into the right crystal phase without expensive or toxic steps, and the SRBW method appears to address that bottleneck by using sound waves rather than aggressive chemicals or high-temperature treatments, potentially lowering both cost and environmental impact.
From Lab Film to Embedded Sensor
The practical question is whether a thin polymer film can do useful work outside a controlled laboratory. The car run-over test is a start, but real deployment in tires, road surfaces, or wearable health monitors would demand consistent output across temperature swings, moisture exposure, and millions of stress cycles rather than thousands. The 20,000-cycle figure, while impressive for an academic proof of concept, represents a fraction of what a tire-embedded sensor would experience over a vehicle’s lifetime, or what a shoe insole or industrial floor mat would see in continuous use. No independent replication of the electroacoustic processing method has been reported yet, and the study does not include head-to-head stress-test comparisons against PVDF films under identical conditions, leaving open questions about long-term drift, delamination, and performance under combined bending and compression.
Still, the combination of high voltage output, mechanical toughness, and PFAS-free chemistry addresses three problems that have stalled flexible energy harvesting for years. Earlier work on wearable and implantable devices, such as self-powered biosensors that scavenge energy from motion, has shown how even modest power levels can be enough to run low-energy electronics if the harvesting material is reliable and conformable. By pushing nylon-11 into a strongly piezoelectric regime with SRBW processing, the RMIT team has effectively expanded the design space for such systems to include a polymer that is already familiar to industry and less contentious from a regulatory standpoint. If future studies can validate long-term stability and demonstrate integration with real-world packaging (such as laminates, encapsulants, and conductive textiles), the technology could move from a striking laboratory demonstration to a practical building block for smart infrastructure and wearable electronics.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
