SUPPLEMENTARY INFORMATION
1. Literature overview of normalized MSDs for various Hard Sphere fluids
In Fig 1. we make a comparison between the Mean Squared Displacements of various
Hard Sphere (HS) systems from literature, including our silica suspensions in DMSOWater (plus 0.01 M LiCl) as reported in this paper. Normalizing all data as <Δr2>/d2 and
τ/τr (with τr =d2/4D0 and D0 the diffusion coefficient at infinite dilution), all data at the
same HS volume fraction should collapse onto a mastercurve.
10
2
0,01
<r >/d
0,1
2
1
1E-3
1E-4
0,01
0,1
1
10
100
1000
10000
r
Fig. 1 (Color online) MSD data for various (near) Hard Sphere systems.
Our study:solid black symbols; 0.16 (■), 0.26 (●), 0.37(▲), 0.42(▼), 0.52(♦), 0.54(◄), 0.57(►)
Kasper et al [27]: solid red symbols; 0.32 (■), 0.40 (●), 0.48(▲), 0.52(▼), 0.56(♦), 0.60(◄)
Weeks et al [9]: black open symbols; 0.46 (■), 0.52 (●), 0.53(▲), 0.56(▼), 0.60(♦)
Kegel et al [15]:red open symbols; 0.45 (■), 0.48 (●), 0.52(▲), 0.57 (▼) 0.60(♦)
The comparison makes clear that first of all, rather different (normalized) time regimes
were addressed by the various studies. The data from Kegel et al and Weeks et al address
the longest times whereas the data of Kasper et al and our data are in the short time
regime. The two datasets at large times have closely corresponding volume fractions but
near-quantitative agreement between the MSDs occurs only for φ = 0.46-0.52. The data
sets at short times show several nearly overlapping curves but the volume fractions do not
correspond.
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2. Particle size dsitribution
Fig. 2 shows a Scanning Electron Microscopy image of our silica particles, and the size
distribution obtained from this image.
Fig. 2 (Color online): SEM image of our silica particles, and the size histogram
Fitting with a Gauss distribution yielded an average diameter of 1.15 μm and a standard
deviation of 8% (92 nm). This fitting curve, indicated with red dots, ignores two particles.
For calculating volume fractions, the average particle volume π<d3>/6 is generally more
appropriate than taking π<d>3/6. However for the present distribution the difference
between <d3>1/3 and <d> was ≈ 12 nm.
In figure 3, we show the variation of overall volume fraction (OVF) as a function of H.
Variation of OVF can also be extracted from Figure 6 as averaging over local volume
fractions give OVF.The variation in OVF is less than %5 and does not follow a trend.
2
Volume fraction ()
0,42
0,40
0,38
0,36
0,34
0,32
5
10
15
20
H (m)
Figure 3 Overall volume fraction calculated for varying H for three samples used in experiments.
The volume of calculation has been 65*65*H µm3. The volume fraction has been calculated by
counting number of particles in the box, correcting for the particles at the edges and multiplying with
the mean particle volume.
3. Alternative versions for Figure 5 and Figure 6
3
2
2
<r >=10 s (m )
0.1
0.01
H
1E-3
1E-4
1
10
ZFP (m)
Figure 4 of Appendix. Alternative version of Figure 5: Dark solid line with open squares correspond to
interpolated MSD(t=10s) with Peak values taken from Figure 6. FIG. 5: Spatially resolved behavior of
MSD(τ =10s) for the fluid at φ=0.33, confined at different gap heights H. Correspondence between H (µm)
and symbols: 20 (■), 16(●), 12(▲), 8(▼) and 4(♦). The  symbol belongs to the experiment where the
second confining surface is far away ( H   ). Corresponding open symbols indicate ‘bulk’ MSD values
calculated from the local volume fraction showing what MSD(τ=10s) would be if the system was bulk and
dynamics solely governed by volume fraction. The open symbols has been calculated from the linear fit to a
characteristic curve in the inset of Figure 6. The error bars has been calculated from different fits to inset
of Figure 6. The dotted part of open symbols indicate extrapolation.See text for further details.
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1.0
C O N V O L U T
ED
0 .6
0.8
0.6
0 .5
0 .4
0 .3
0 .2
0 .1
s
0 .0
2
4
6
8
10
12
14
16
18
20
22
24
Z ( m )
0.4
0.2
0.0
0
10
20
30
Z(m)
Figure 5 of Appendix.Alternavive version of Figure 6 indicating the peak values used for calculation in
Figure 5 with open symbols. FIG. 6 (color online): Geometirc Volume fraction(φ s) vs Z-direction for
different confinement gaps: Correspondence between H (µm) and symbols: 20 (■), 16(●), 12(▲), 8(▼) and
4(♦). The  symbol belongs to the experiment where the second confining surface is far away ( H   ).
φ indicates local volume fraction calculated in a bin. Inset: Convoluted volume fraction(φ) vs Z-histogram,
as needed for generating reference MSD data at τ=10 s in Fig. 5. Plot symbols indicate which φ values
were used for this purpose. See text for further details.
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