It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, March 11, 2026
Polymers that crawl like worms: How materials can develop direction without being told where to go
New findings can help to better understand DNA dynamics in living cells
Figure 1: Chain in the forest of obstacles. The tip of orange segment (stronger fluctuations than acting on the grey segment) has three options to move forward (dashed arrows) and only one to move backwards (along the chain).
Researchers at the University of Vienna have uncovered a surprising phenomenon: polymer chains with segments that simply fluctuate at different intensities can spontaneously develop directional, persistent motion when densely packed – even though nothing in the system points them in any particular direction. This "entropic tug of war," driven by fundamental physical constraints, could help explain how DNA organizes and moves inside living cells, and may lead to new materials. The study was currently published in Physical Review X.
"Think of a chain threaded through a dense forest of trees, which represent obstacles posed by the other chains in the system. One end of the chain is being shaken much more vigorously than the other," explains lead author Jan Smrek from the Faculty of Physics at the University of Vienna. "You might expect it to just wiggle randomly in place. But we found that because the chain has to find its way by going in-between the trees, the difference in shaking intensity creates an imbalance that actually propels the entire chain forward through the forest."
This refers to a polymer, a large molecule consisting of many units linked together in a long chain, such as DNA. The Viennese research team – Adam Höfler, Iurii Chubak, Christos Likos and Jan Smrek – used computer simulations and analytical theory to show that this directed motion arises purely from topological constraints. When polymer chains are entangled and cannot pass through each other, segments with stronger fluctuations generate larger entropic forces (See Figure.1 for explanation). This creates an imbalance that pushes the entire chain forward along its own contour, with the stronger fluctuating part acting as the “head of the snake” moving through the forest of obstacles.
Unlike previous active polymer models that build upon directional forces, this mechanism requires only a difference in fluctuation magnitude between segments. The finding has direct relevance to chromatin – the complex of DNA and proteins in cell nuclei. Various cellular processes like transcription and DNA repair create localized regions of enhanced activity along the chromatin fiber. The researchers' work suggests these activity differences alone could drive the coherent chromatin motions observed in living cells.
The study also reveals how the dynamics depend on the degree of chain entanglement. At higher densities, the directed motion becomes faster and more pronounced. The researchers found that individual segments can exhibit superdiffusive motion – moving faster than random diffusion would predict – on intermediate timescales.
"This work bridges materials science and biology," says Smrek. "We're showing that the same physics that governs synthetic polymers can explain behaviors in living systems. And it suggests we could design new materials that spontaneously develop directed transport properties," adds Smrek.
The findings open new avenues for creating functional active materials and provide a framework for interpreting chromatin dynamics experiments. They could further investigate how these effects combine with other active processes in biological systems and explore applications in smart materials that could transport cargo or heal themselves.
The research was supported by the European Union through the QLUSTER project. This project builds on Adam Höfler's Master's thesis under supervision of Jan Smrek.
Summary:
Polymer chains with segments that fluctuate at different magnitudes spontaneously develop persistent, directed motion when densely packed
The mechanism arises from an imbalance in entropic forces at chain ends due to topological constraints – chains cannot cross each other
No built-in directional forces are needed; the difference in fluctuation magnitude alone drives the effect
The findings help explain chromatin dynamics in living cells and could enable new self-propelling materials
Individual segments exhibit superdiffusive motion, moving faster than random diffusion on intermediate timescales
About the University of Vienna:
At the University of Vienna, curiosity has been the core principle of academic life for more than 650 years. For over 650 years the University of Vienna has stood for education, research and innovation. Today, it is ranked among the top 100 and thus the top four per cent of all universities worldwide and is globally connected. With degree programmes covering over 180 disciplines, and more than 10,000 employees we are one of the largest academic institutions in Europe. Here, people from a broad spectrum of disciplines come together to carry out research at the highest level and develop solutions for current and future challenges. Its students and graduates develop reflected and sustainable solutions to complex challenges using innovative spirit and curiosity.
Over the past century, the amount of carbon dioxide in the atmosphere has increased dramatically. This rise has contributed to global warming and led to many harmful effects, including shifting weather patterns and more frequent droughts. There is an urgent need to lower the amount of carbon dioxide in the air to protect ecosystems and reduce future damage to the planet.
Paul V. Galvin professor Petra Fromme in ASU’s School of Molecular Sciences (SMS), and her team, have taken an important step toward improving technologies that pull carbon dioxide directly from the air—an approach considered essential for tackling climate change. The team closely examined two promising materials that can capture CO₂ using changes in humidity, a low‑energy process known as “moisture‑swing” direct air capture (DAC). Fromme is also Director of the Biodesign Institute’s Center for Applied Structural Discovery,
The team includes Gayathri Yogaganeshan, Raimund Fromme and Michele Zacksfrom SMS, Rui Zhangfrom ASU’s Eyring Materials Center , Jennifer Wade and Golnaz Najaf Tomaraeifrom TheSteve Sanghi College of Engineering, NAU, Sharang Sharangfrom Tescan USA Inc., Warrendale, Pennsylvania, Douglas Yates from the Singh Center for Nanotechnology, UPENN, Philadelphia, Pennsylvania, Marlene Velazco Medel fromthe Center for Negative Carbon Emissions, ASU, Martin Uherfrom the Tescan Group a.s., Brno, Czech Republic and Justin Floryfrom the Walton Center for Planetary Health, ASU.
“This work is so important as it shows for the first time the structural characterization of two direct air capture materials with a unique combination of techniques ranging from X-ray diffraction to electron microscopy and atomic force microscopy which we combined with functional studies on the moisture swing mechanisms of carbon dioxide binding and release,” explains Fromme.
Gayathri Yogaganeshan, Fromme’s doctoral student, is first author on the paper just published in Materials Today Chemistry.
"Our research addresses the urgent challenge of removing carbon dioxide from the atmosphere by investigating materials for low-energy, moisture-driven direct air capture,” says Yogaganeshan .
Many carbon reduction methods focused on remediation have been explored. These include reforestation, agricultural and soil management, C-biomineralization, ocean fertilization, and bioenergy generation with carbon capture and storage (BECCS). Direct Air Capture, together with permanent storage, is a promising alternative method that captures carbon dioxide directly from the air.
This study looks at two commercially available polymers, Fumasep FAA-3 and IRA-900, to see how well they work for a low-energy carbon capture method called moisture-driven direct air capture (DAC). The goal was to understand how the structure of these materials affects how they adsorb and release carbon dioxide (CO₂).
Researchers used several imaging and X-ray techniques to examine the materials’ structures at different scales. They also ran experiments that measured how much CO₂ and water the materials adsorbed and released under different humidity levels.
The results showed that both materials behave similarly when adsorbing and releasing water, suggesting that water movement is controlled mainly by their molecular structure. However, their ability to capture CO₂ differed. The material with larger pores, IRA-900, captured more CO₂ and did so more quickly. Additional imaging revealed features like pores, clustering, and swelling that help explain these differences.
Overall, the study provides insight into how these materials work during CO₂ capture and highlights the important role of moisture. This knowledge could help researchers design more energy-efficient materials for carbon capture in the future.
“Using advanced structural characterization techniques including X-ray diffraction, SAXS/WAXS, atomic force microscopy, FIB-SEM, and TEM, combined with moisture-swing sorption experiments, we linked molecular-scale ordering, pore architecture, and hydration dynamics to CO₂ uptake and release,” explains Yogaganeshan.
“We found that hydration dynamics are controlled primarily by molecular structure, while CO₂ sorption kinetics and capacity are strongly influenced by macropore architecture and charge site density, with more open structures exhibiting enhanced uptake and faster initial kinetics. Surface analyses confirmed clustering, porosity, and swelling, revealing how subtle structural features govern performance. These insights provide a foundation for designing more energy-efficient materials for scalable carbon dioxide removal, with implications for advancing practical carbon capture technologies."
In a study published in Angewandte Chemie International Edition, a team led by Profs. BAO Xinhe, GAO Dunfeng, and ZHANG Guohui from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, along with Prof. WANG Guoxiong from Fudan University, achieved efficient bicarbonate-mediated integrated carbon dioxide (CO2) capture and electrolysis to CO through an ionomer-driven reaction microenvironment control strategy.
Traditional CO2 capture and conversion routes from industrial flue gas typically follow a "capture-release-compression-electrolysis" tandem pathway. The bicarbonate-mediated integrated CO2 capture-electrolysis route, as an emerging reactive carbon capture technology, couples upstream CO2 capture with subsequent electrocatalytic conversion, reducing the energy consumption associated with obtaining high-purity CO2 feedstock.
The electrolysis of bicarbonate capture liquids is a crucial step in the bicarbonate-mediated integrated CO2 capture-electrolysis route. However, this step suffers from insufficient current density (low reaction rate) and high cell voltage (low energy efficiency).
In this study, the researchers manipulated the reaction microenvironments by introducing ionomers into cobalt phthalocyanine (CoPc) electrodes, improving the performance of bicarbonate electrolysis. In a cation exchange membrane-based zero-gap electrolyzer, the CoPc electrode modified with a Nafion ionomer exhibited a high CO Faradaic efficiency of 93% at an applied current density of 300 mA cm−2 and a CO partial current density of 410 mA cm−2 at a low cell voltage of 3.09 V.
Electrode structure characterization and finite element simulation results demonstrated that the proton conductivity of the Nafion ionomer increased the local concentration of in situ generated CO2 (i-CO2) in the proximity of the CoPc catalyst, resulting in improved CO formation.
Furthermore, the researchers demonstrated a closed-loop CO2 capture and electrolysis cycle at the device level using the Nafion-incorporated CoPc electrode and a simulated flue gas.
"Our study shows the potential of the reaction microenvironment control strategy for improving bicarbonate electrolysis performance and advancing reactive carbon capture technology," said Prof. GAO.
Researchers have developed a practical and low cost method to transform agricultural waste into high quality biochar, significantly increasing its ability to store carbon and help combat climate change. The study demonstrates that a simple treatment using limewater can dramatically improve the efficiency of biochar production while keeping the process accessible for use directly in the field.
Biochar is a carbon rich material produced when plant biomass is heated in low oxygen conditions. Because the carbon in biochar remains stable in soil for long periods, scientists consider it a promising carbon negative technology that can help remove carbon dioxide from the atmosphere. However, traditional biochar production typically requires specialized equipment and energy intensive processes, which limit large scale adoption.
In the new study, researchers explored a simple alternative inspired by natural burning processes. Instead of using industrial reactors, they combined open burning with a limewater treatment to improve carbon retention during the carbonization of orchard waste. The team tested this approach using pruned branches from Litchi trees, a common agricultural residue in southern China.
“Our goal was to develop a biochar production method that farmers could potentially use directly in orchards without expensive equipment,” said the study’s corresponding author. “By combining limewater treatment with a rapid water quenching process, we were able to significantly enhance carbon retention while maintaining a simple production method.”
The process works through a combination of chemical and physical mechanisms. Before burning, branches are immersed in limewater, allowing calcium compounds to penetrate and coat the biomass. When the branches are ignited, the outer layer burns quickly while the interior undergoes oxygen limited carbonization. The material is then rapidly quenched with water or limewater, preserving the carbonized structure and producing biochar.
The results showed that the limewater treatment dramatically improved performance. Biochar produced without treatment converted about 52 percent of the original biomass carbon into stable char. With limewater immersion and coating, the carbon conversion rate increased to approximately 86 percent.
The treated biochar also showed important improvements in structure and chemistry. It exhibited a much larger specific surface area and contained higher levels of oxygen containing functional groups, both of which are important for soil improvement and environmental applications. Microscopic and chemical analyses revealed that calcium compounds formed a protective barrier during combustion, helping prevent carbon from being oxidized into gases.
According to the researchers, the technique could have important implications for agricultural sustainability. Litchi orchards produce large amounts of pruned branches each year, which are often burned or discarded. Converting this biomass into biochar using the new method could turn a waste problem into a climate solution.
The study estimates that applying this strategy in Litchi orchards could sequester roughly 6000 kilograms of carbon per hectare, equivalent to about 22,000 kilograms of carbon dioxide. This amount could potentially offset a substantial portion of the carbon emissions associated with orchard cultivation.
“This approach shows how agricultural waste can be transformed into a valuable resource,” the researchers noted. “Local production and local use of biochar could help farmers reduce emissions while improving soil health and supporting more sustainable agricultural systems.”
The researchers believe the simplicity and scalability of the technique make it particularly promising for rural and developing regions where access to advanced biochar production facilities may be limited. With further development, this method could contribute to broader efforts to reduce agricultural emissions and enhance carbon sequestration worldwide.
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Journal Reference: Xiao, L., Li, W., Wu, J. et al. Enhanced carbon retention in Litchi biochar via in-situ limewater coating and self-limited oxygen pyrolysis regulated by water-fire interaction. Biochar8, 27 (2026).
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.
