Figure 4.

Revealed conformational changes in CMD layers in terms of hydration and viscoelastic properties, based on our developed data analysis methodology and the resulted composite graphs. The illustrations on the top demonstrate the assumed conformational changes in the formed CMD layer, relating to certain experimental phases (times) which are indicated in the corresponding graphs by α, β and γ, respectively. The numbers in the headers indicate the experimental sections which are detailed in Fig. 2. Graph A and B represent the adlayer refractive index (n_A) and hydration (φ_A) as well as mechanical and optical thickness data (d_A^OWLS and d_A^QCM,V) obtained at the whole experimental timescale. Graph B shows the thicknesses originating from both the OWLS and QCM-I measurements, using the same hydrated thickness data of graph D in Fig. 3. The values of n_A and d_A were calculated from OWLS measurements using the isotropic homogenous 4-layer mode equations. The estimated (realistic) refractive index of the CMD layer (n_A,est) was also calculated, based on the known refractive index of bulk dextran and determined hydration degree. These n_A,est values (1.33–1.36) provided a practical boundary for the isotropic-anisotropic transition (shown in graph A,C and D). Graph C was compiled from n_A and φ_A data of graph A, providing useful physical parameters over the measured dry CMD masses (M_A^OWLS). In the inset of graph C, the refractive index ellipsoid demonstrates the observed negative birefringence in the adlayer (n_A,o > n_A,e). Graph D combines the magnitude of anisotropy (n_A) with layer viscosity (η_A), where the latter quantity was independently determined from QCM-I.