Distinctive Features of the Buffer Capacity of Polyelectrolyte Microcapsules Formed on MnCO3 Core

The development of layer-by-layer polyelectrolyte microcapsules (PMCs) with defined buffer capacity (BC) is a key task for creating stable systems in biomedicine and materials science. Manganese carbonate (MnCO3), which shares properties with CaCO3 and the ability to form hollow structures, represents a promising alternative. However, its interaction with polyelectrolytes and its influence on BC remain insufficiently studied. This research focuses on determining the BC of PMCs templated on MnCO3 cores under varying ionic strength (0.22–3 M NaCl) and temperature (60–90 °C), as well as comparing the results with PMCs templated on CaCO3 and PS cores. It was found that MnCO3-based PMCs (PMCMn) exhibit hybrid behavior between CaCO3- and PS-based PMCs: the BC dynamics of PMCMn and CaCO3-based PMCs (PMCCa) in water are identical. At different ionic strength at pH < 5, the BC of PMCMn and PS-based PMCs (PMCPS) remains unchanged, while at pH > 8.5, the BC of PMCMn increases only at 3 M NaCl. The BC of PMCMn remains stable under heating, whereas the BC of PMCCa and PMCPS decreases. These results confirm that the choice of core material dictates PMC functionality, paving the way for adaptive systems in biosensing and controlled drug delivery.