Fig. 1: Interfacial response of thermo-responsive PNIPAM microgels.

a Previously proposed destabilisation mechanisms: covered interface to fluidised interface with lower coverage due to (i) shrinkage, (ii) desorption, or (iii) weakening of the interface due to aggregation. b Interfacial shear rheology with double wall ring geometry. c–j Interfacial rheological response to changing temperature: c–f Oscillatory strain amplitude sweep for (c) ultra-low crosslinked (ULC) microgels at a frequency f = 0.1 Hz, microgels with (d) 1 mol% crosslinker, (e) 5 mol% crosslinker and (f) 10 mol% crosslinker at f = 0.2 Hz. Storage (G^s′, filled) and loss (G^s″, open) moduli with strain amplitude, γ₀, at low temperature, T < T_VPT (blue), and high temperature, T > T_VPT (red). The shading indicates the resolution limit⁸¹. g–j Linear viscoelastic response with increasing T: (g) ULC microgels at γ₀ = 0.05, (h–j) microgels with (h) 1 mol% crosslinker, (i) 5 mol% crosslinker and (j) 10 mol% crosslinker each at γ₀ = 0.01.