Table 1.

Material parameters at T = 25 °C.

Water
Density 23	ρ0	997 kg m−3
Speed of sound 23	c0	1497 m s−1
Shear viscosity 23	μ	0.890 mPa s
Bulk viscosity 24	μb	2.47 mPa s
Compressibility*	κ0	448 TPa−1
Lithium niobate (LiNbO3)
Speed of sound 25	csub	3994 m s−1
Polydimethylsiloxane (PDMS, 10:1)
Density 26	ρwall	920 kg m−3
Speed of sound 27	cwall	1076.5 m s−1
Attenuation coeff. (6.65 MHz) † 27		31 dB/cm
Polystyrene
Density 23	ρp	1050 kg m−3
Speed of sound 28 (at 20 °C)	cp	2350 m s−1
Poisson’s ratio 29	σp	0.35
Compressibility‡	κp	249 TPa−1
Acoustic actuation parameters
Wavelength (set by IDTs)	λ	600 μm
Forcing frequency	f	6.65 MHz
Displacement amplitude	u0	0.1 nm
Displacement decay coefficient	Cd	116 m−1

^*Calculated as ${\kappa }_0=1/({\rho }_0{c}_0^2)$

^†Calculated via power law fit to data by Tsou et al. ²⁷

^‡Calculated as ${\kappa }_{\mathrm{p}}=\frac{3(1-{\sigma }_{\mathrm{p}})}{1+{\sigma }_{\mathrm{p}}}\frac{1}{({\rho }_{\mathrm{p}}{c}_{\mathrm{p}}^2)}$ from Landau and Lifshitz. ³⁰