Commemorating the 145th anniversary of his birth and exploring his revolutionary work on colloidal systems
In our everyday lives, we encounter countless substances that are neither true solutions nor coarse suspensions—milk, blood, fog, and ink. These in-between substances, known as colloids, form a state of matter that is fundamental to both biological life and modern technology. The scientist who helped illuminate this mysterious middle ground was Academician Anton Dumansky, a pioneering Ukrainian chemist whose work laid the foundation for our modern understanding of colloidal systems. As we commemorate the 145th anniversary of his birth, we explore how Dumansky's fascination with this "in-between" world of particles revolutionized multiple scientific disciplines.
Milk, blood, fog and ink are common colloidal systems we encounter daily
Colloids represent a distinct state of matter with unique properties
Dumansky's work established colloidal chemistry as a distinct field
Anton Vasilyevich Dumansky (1880-1967) was a pivotal figure in colloidal chemistry during a period when the field was still in its formative stages. His career spanned the first half of the 20th century, a time of remarkable advancement in physical chemistry.
Dumansky's most significant contribution was establishing the fundamental importance of hydration (the binding of water molecules) to the stability of colloidal systems. While other scientists recognized electrical charges as stabilizing factors in colloids, Dumansky demonstrated that water molecules forming organized layers around colloidal particles were equally crucial to preventing aggregation. This insight was revolutionary for its time.
His persistent research led to the creation of the first Soviet scientific school of colloidal chemistry at the Institute of General and Inorganic Chemistry of the Ukrainian SSR Academy of Sciences. Through both experimental evidence and theoretical frameworks, Dumansky argued that colloidal phenomena represented a special state of matter rather than just a transitional phase—a concept that gained gradual acceptance within the scientific community.
Birth of Anton Vasilyevich Dumansky
Begins research in colloidal chemistry, focusing on hydration phenomena
Establishes the importance of hydration in colloidal stability
Passing of Academician Dumansky, leaving a substantial scientific legacy
Dumansky established that organized water layers around colloidal particles are crucial for stability
Founded the first Soviet scientific school of colloidal chemistry
What exactly are colloidal dispersions? They represent a unique state of matter where one substance is finely dispersed within another, with the dispersed particles ranging in size from 1 nanometer to 1 micrometer. This special size range gives colloids their distinctive properties, different from both true solutions and coarse suspensions.
Colloidal systems are classified based on the states of the dispersed phase and dispersion medium. The stability of these systems—what prevents the particles from clumping together and settling out—depends on two key factors: electrical charges that cause particles to repel each other, and protective hydration shells that form physical barriers between particles. Dumansky's pioneering work particularly advanced understanding of the latter stabilization mechanism.
To appreciate the practical challenges and nuances of colloidal chemistry that Dumansky helped elucidate, we can examine a contemporary laboratory procedure that studies colloidal stability. The following experiment investigates sulfur colloid formation and explores how various factors affect its stability 1 .
The experimental process involves careful preparation and observation across multiple test conditions 1 :
| Tube | 30 Minutes | 2 Hours | 18-24 Hours | Resuspension Difficulty |
|---|---|---|---|---|
| A | Hazy | - | - | - |
| B | Uniformly cloudy | - | - | - |
| C | Clear with precipitate | - | - | - |
| G | XXX | Precipitate formed | Increased precipitation | Unable to fully resuspend |
| Tube | μg Al³⺠| Buffer | Appearance at 18-24 hours |
|---|---|---|---|
| D | 0 | Present | Hazy, stable |
| G | 40 | Present | Heavy precipitate |
| I | 80 | Present | Complete precipitation |
| Tube | Al³⺠Level | EDTA:Al³⺠Ratio | Description at 18-24 hours |
|---|---|---|---|
| P | Medium | 2:1 | Hazy, no precipitation |
| R | Highest | 2:1 | Clear, stable |
This comprehensive experiment investigates three distinct aspects of colloidal behavior 1 :
Tubes A-C examine how gelatin affects hydrophobic colloids, acting as a "protective colloid" that prevents sulfur particles from aggregating 1 .
Tubes D-L demonstrate how aluminum ions (Al³âº) can destabilize colloids, testing threshold levels where stability is maintained versus precipitation occurs 1 .
Tubes M-R explore how EDTA counteracts destabilizing effects of aluminum ions by chelating them 1 .
Understanding the function of key reagents is essential to grasping colloidal chemistry experimentation. The following table outlines crucial components used in the sulfur colloid experiment and their roles in colloidal systems 1 .
| Reagent | Function in Colloid Chemistry |
|---|---|
| Gelatin | Acts as a protective colloid; adsorbs onto sulfur particles creating a protective layer that prevents aggregation through steric stabilization 1 |
| Sodium Thiosulfate | Source of sulfur ions; under acidic conditions and heat, it decomposes to form fine elemental sulfur particles that create the colloidal dispersion 1 |
| Hydrochloric Acid (HCl) | Provides acidic conditions necessary for the decomposition of thiosulfate to form sulfur particles 1 |
| Aluminum Ions (Al³âº) | Destabilizing agent; their positive charge can neutralize negatively charged colloidal particles, causing aggregation and precipitation 1 |
| EDTA | Chelating agent; binds to aluminum ions in solution, preventing them from interacting with and destabilizing the colloidal particles 1 |
| Buffer Solutions | Maintain constant pH, which is crucial as it affects the charge on gelatin molecules and consequently their protective ability 1 |
| Research Chemicals | 6-(2-Fluorophenyl)-1,3-dioxolo(4,5-g)quinolin-8(5H)-one |
| Research Chemicals | Cpypp |
| Research Chemicals | 4-(4-(2,3-dihydrobenzo(1,4)dioxin-6-yl)-5-pyridin-2-yl-1H-imidazol-2-yl)benzamide |
| Research Chemicals | D77 |
| Research Chemicals | DC_05 |
Relative importance of reagents in colloidal stability experiments
At the isoelectric point, gelatin has a net charge of zero and is least effective at stabilization, highlighting the importance of pH control in colloidal systems 1 .
This instruction helps determine whether sedimentation is reversible, providing insights into the nature of colloidal instability 1 .
Dumansky's fundamental research on colloidal hydration has found practical applications across diverse fields. His insights help explain various natural and technological phenomena, building directly on his foundational work establishing the importance of hydration in colloidal stability.
The colloidal nature of cytoplasm and blood
Stability of milk, mayonnaise, and other emulsified products
Formulation of suspensions and gels for drug delivery
Development of paints, inks, and coatings
Treatment of water and wastewater
The modern laboratory experiment exploring sulfur colloid stability directly builds upon Dumansky's foundational work. When researchers today investigate how gelatin protects colloidal particles or how ions disrupt colloidal stability, they are working within theoretical frameworks that Dumansky helped establish.
On the 145th anniversary of his birth, Academician Anton Dumansky's legacy continues to influence how scientists understand and manipulate the colloidal state. His insistence on the importance of hydration forces, once a novel concept, is now standard knowledge in colloidal science. The modern experiment with sulfur colloid serves as a testament to how Dumansky's pioneering work continues to inform contemporary laboratory practice and theoretical understanding.
Though the instruments have grown more sophisticated, the fundamental questions about colloidal stability that Dumansky investigated remain actively explored in labs worldwide—a fitting tribute to a scientist who dedicated his life to illuminating the fascinating in-between world of colloids.