Figure 6.

Changes in frequency (Δf) and dissipation (ΔD) recorded during QCM-D experiments using (a) PEG₅₀₀₀- and (b) PEG₃₅₀-QDs. Decreases in f indicate an increase in deposited mass (including coupled waster). Increases in D correspond to increases in the viscoelasticity of the attached mass (i.e., less coupling of the vibrations of the crystal). Labels at the top of the plots indicate times when liquid phase composition was altered. Quantum dot number concentration was 2 μM (i.e. 1 × 10¹⁸ QD·L⁻¹) in 0.03 M NaCl at pH 4.