Salt ions can control supraparticle structure during spray-drying of colloids, but they affect functionality–Volatile ammonium carbonate offers a smart workaround
Year: 2025
Type: article
Abstract: Salts were found to be useful in order to manipulate the structure formation and shaping of supraparticles during spray-drying. However, commonly utilized salts such as calcium chloride (CaCl 2 ) remain in the framework of the supraparticles and thus, potentially interfere with the properties of the supraparticles. In this study, ammonium carbonate ((NH 4 ) 2 CO 3 ) is introduced as a structure-directing agent and compared to CaCl 2 . Due to its thermal decomposability into gaseous species, (NH 4 ) 2 CO 3 can be completely post-synthetically removed by a simple heat treatment. Thus, undesired washing steps of the supraparticle products are avoided and interferences of the salt with the functional properties of supraparticles are eliminated. These advantages are highlighted for the example of hydrogen-indicating gasochromic supraparticles. In summary, (NH 4 ) 2 CO 3 acts as a structure-directing agent without affecting the intrinsic properties of the supraparticles, making it suitable for application in systems were residual salt is undesired. • Salt serves as structure-directing agent during spray-drying. • Commonly used salts can interfere with supraparticle properties. • Washing steps remove disruptive interferences but risk compromising functionality. • Ammonium carbonate decomposes at mild temperatures, eliminating post-processing removal needs and offering a smart workaround.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,470
Funder: Deutsche Forschungsgemeinschaft
OpenAlex ID: W4416197986