We consider the influence of both of these effects on the observability of stable particle clusters and suspensions.

At zero temperature, the Casimir force $F$ is determined by an integral $F = \int_0^\infty d\xi f(\xi)$ of a complicated integrand $f(\xi)$ evaluated at imaginary frequencies $\xi$ [@Lifshitz80]. At $T > 0$, the integral is replaced by a finite sum over Matsubara frequencies $\omega_n =2\pi n k T/\hbar$, arising from the poles of the $\coth$ photon distribution along the imaginary frequency axis  [@schwinger78; @Bordag], leading to a force $F_T$ given by: $$F_T = \frac{2\pi k T}{\hbar} \left[\frac{f(0+)}{2} + \sum_0^\infty
    f\left(\frac{2\pi kT}{\hbar}n\right)\right],$$ which is exactly a trapezoidal-rule approximation to the zero-temperature force with a discretization error determined by the Matsubara wavelength $\lambda_T = 2\pi c / \xi_T = \hbar /
kT$ [@boyd01:book]. Because the integrand $f(\xi)$ is smooth and typically varies on a scale much slower than $1/\lambda_T$, where $\lambda_T = 7.6\,\mu$m at room temperature $T=300$ K, the finite-$T$ correction to the zero-temperature Casimir force is often negligible [@milton04]. However, in fluids, as is the case here, larger temperature effects have been obtained  [@RodriguezW10:PRL] by dispersion-induced oscillations in $f(\xi)$, and so we must check our previous zero-temperature predictions against finite-$T$ calculations. For the 