| Many historical buildings were built of limestone, such as Vienna’s St. Stephen’s Cathedral. Limestone is easy to work with, but does not withstand weathering well. It consists mainly of calcite minerals that are relatively weakly bound to each other, which is why parts of the stone keep crumbling away over the years, often requiring costly restoration and conservation treatments. | |
| However, it is possible to increase the resistance of the stone by treating it with special silicate nanoparticles. The method is already being used, but what exactly happens in the process and which nanoparticles are best suited for this purpose has been unclear until now. | |
| A research team from TU Wien and the University of Oslo has now been able to clarify exactly how this artificial hardening process takes place through elaborate experiments at the DESY synchrotron in Hamburg and with microscopic examinations in Vienna. That way, the team could determine which nanoparticles are best suited for this purpose. |
An aqueous suspension with nanoparticles |
|
| “We use a suspension, a liquid, in which the nanoparticles initially float around freely,” says Prof. Markus Valtiner from the Institute of Applied Physics at TU Wien. “When this suspension gets into the rock, then the aqueous part evaporates, the nanoparticles form stable bridges between the minerals and give the rock additional stability.” | |
| This method is already used in restoration technology, but until now it was not known exactly what physical processes take place. When the water evaporates, a very special kind of crystallisation occurs: Normally, a crystal is a regular arrangement of individual atoms. However, not only atoms, but also entire nanoparticles can arrange themselves in a regular structure – this is then referred to as a “colloidal crystal”. | |
| The silicate nanoparticles come together to form such colloidal crystals when they dry in the rock and thus jointly create new connections between the individual mineral surfaces. This increases the strength of the natural stone. | |
Measurements at the large-scale research facility DESY and in Vienna |
|
| To observe this crystallisation process in detail, the TU Wien research team used the DESY synchrotron facility in Hamburg. Extremely strong X-rays can be generated there, which can be used to analyse the crystallisation during the drying process. | |
| “This was very important to understand exactly what the strength of the bonds that form depends on,” says Joanna Dziadkowiec (University of Oslo and TU Wien), the first author of the publication in which the research results have now been presented (Langmuir, “Cohesion Gain Induced by Nanosilica Consolidants for Monumental Stone Restoration”). “We used nanoparticles of different sizes and concentrations and studied the crystallisation process with X-ray analyses.” It was shown that the size of the particles is decisive for optimal strength gain. | |
| To this end, the TU Vienna also measured the adhesive force created by the colloidal crystals. For this purpose, a special interference microscope was used, which is perfectly suited for measuring tiny forces between two surfaces. | |
Small particles, more force |
|
| “We were able to show: The smaller the nanoparticles, the more can they strengthen the cohesion between the grains of minerals,” says Joanna Dziadkowiec. “If you use smaller particles, more binding sites are created in the colloidal crystal between two grains of minerals, and with the number of particles involved, the force with which they hold the minerals together thus also increases.” | |
| How many particles are present in the emulsion is also important. “Depending on the particle concentration, the crystallisation process proceeds slightly differently, and this has an influence on how the colloidal crystals form in detail,” says Markus Valtiner. The new findings will now be used to make restoration work more durable and more targeted. |
News
How to prevent chronic inflammation from zombie-like cells that accumulate with age
In humans and other multicellular organisms, cells multiply. This defining feature allows embryos to grow into adulthood, and enables the healing of the many bumps, bruises and scrapes along the way. Certain factors can [...]
Breakthrough for long Covid patients who lost sense of smell
A breakthrough nasal surgery has restored the sense of smell for a dozen long Covid patients. Experts at University College London Hospitals NHS Foundation Trust successfully employed a technique typically used for correcting blocked nasal passages, [...]
Scientists Invent Plastic That Can Dissolve In Seawater In Just A Few Hours
Plastic waste and pollution in the sea have been among the most serious environmental problems for decades, causing immense damage to marine life and ecosystems. However, a breakthrough discovery may offer a game-changing solution. [...]
Muscles from the 3D printer
Swiss researchers have developed a method for printing artificial muscles out of silicone. In the future, these could be used on both humans and robots. Swiss researchers have succeeded in printing artificial muscles out [...]
Beneficial genetic changes observed in regular blood donors
Researchers at the Francis Crick Institute have identified genetic changes in blood stem cells from frequent blood donors that support the production of new, non-cancerous cells. Understanding the differences in the mutations that accumulate [...]
Shocking Amounts of Microplastics in the Brain – It Could Be Increasing Our Risk of Dementia
The brain has higher concentrations of plastic particles compared to other organs, with increased levels found in dementia patients. In a comprehensive commentary published in Brain Medicine, researchers highlight alarming new evidence of microplastic accumulation [...]
Baffling Scientists for Centuries: New Study Unravels Mystery of Static Electricity
ISTA physicists demonstrate that contact electrification depends on the contact history of materials. For centuries, static electricity has intrigued and perplexed scientists. Now, researchers from the Waitukaitis group at the Institute of Science and [...]
Tumor “Stickiness” – Scientists Develop Potential New Way To Predict Cancer’s Spread
UC San Diego researchers have developed a device that predicts breast cancer aggressiveness by measuring tumor cell adhesion. Weakly adherent cells indicate a higher risk of metastasis, especially in early-stage DCIS. This innovation could [...]
Scientists Just Watched Atoms Move for the First Time Using AI
Scientists have developed a groundbreaking AI-driven technique that reveals the hidden movements of nanoparticles, essential in materials science, pharmaceuticals, and electronics. By integrating artificial intelligence with electron microscopy, researchers can now visualize atomic-level changes that were [...]
Scientists Sound Alarm: “Safe” Antibiotic Has Led to an Almost Untreatable Superbug
A recent study reveals that an antibiotic used for liver disease patients may increase their risk of contracting a dangerous superbug. An international team of researchers has discovered that rifaximin, a commonly prescribed antibiotic [...]
Scientists Discover Natural Compound That Stops Cancer Progression
A discovery led by OHSU was made possible by years of study conducted by University of Portland undergraduates. Scientists have discovered a natural compound that can halt a key process involved in the progression [...]
Scientists Just Discovered an RNA That Repairs DNA Damage – And It’s a Game-Changer
Our DNA is constantly under threat — from cell division errors to external factors like sunlight and smoking. Fortunately, cells have intricate repair mechanisms to counteract this damage. Scientists have uncovered a surprising role played by [...]
What Scientists Just Discovered About COVID-19’s Hidden Death Toll
COVID-19 didn’t just claim lives directly—it reshaped mortality patterns worldwide. A major international study found that life expectancy plummeted across most of the 24 analyzed countries, with additional deaths from cardiovascular disease, substance abuse, and mental [...]
Self-Propelled Nanoparticles Improve Immunotherapy for Non-Invasive Bladder Cancer
A study led by Pohang University of Science and Technology (POSTECH) and the Institute for Bioengineering of Catalonia (IBEC) in South Korea details the creation of urea-powered nanomotors that enhance immunotherapy for bladder cancer. The nanomotors [...]
Scientists Develop New System That Produces Drinking Water From Thin Air
UT Austin researchers have developed a biodegradable, biomass-based hydrogel that efficiently extracts drinkable water from the air, offering a scalable, sustainable solution for water access in off-grid communities, emergency relief, and agriculture. Discarded food [...]
AI Unveils Hidden Nanoparticles – A Breakthrough in Early Disease Detection
Deep Nanometry (DNM) is an innovative technique combining high-speed optical detection with AI-driven noise reduction, allowing researchers to find rare nanoparticles like extracellular vesicles (EVs). Since EVs play a role in disease detection, DNM [...]
