Heat-driven size reduction of biodegradable polyelectrolyte multilayer hollow capsules assembled on CaCO3 template

[Display omitted] •Parg/DS capsules reduce their size and become denser in response to heating.•Thermal response is independent on initial size, layer number and layer sequence.•300 nm Parg/DS hollow capsules are achieved on CaCO3 sacrificial template.•Heating improves the colloidal stability of Parg/DS capsules’ suspensions. Aiming to explore elevated temperatures as a tool for miniaturization of biodegradable polymer multilayer capsules, assembled on spherical vaterite micron- and submicron-sized particles, we subject the shells composed of dextran sulfate (DS) and poly-L-arginine (Parg) to a heat treatment. Changes of the capsule size are studied at various temperatures and ionic strengths of the continuous phase. Unlike some synthetic polymer multilayer shells (their response to heat treatment depends on the number of layers and their arrangement), the biodegradable Parg/DS capsules exhibit size reduction and profound compaction regardless of their initial size, number of polymer layers and polymer layer sequence. The capsule response to heat is stable at ionic strengths of the continuous phase not exceeding 0.1 M NaCl.