Enhancement of Stability of Bubbles to Disproportionation Using Hydrophilic Silica Particles Mixed with Surfactants or Proteins - Food Colloids: Self-Assembly and Material Science - page 366

200

150

100

50

0

0 200 400 600

t / min

Figure 9 Typical bubble radius R versus time t for bubbles stabilized by b -LG at pH ¼ 7
in presence of different concentrations of colloidal silica: & , 0.5 wt% b -LG +
1.5 wt% silica; B , 0.5 wt% b -LG + 3 wt% silica; ' , 0.05 wt% b -LG + 1.5
wt% silica; E , 0.05wt% b -LG + 3 wt% silica. The solid lines indicate the
expected behaviour of 0.05 wt% b -LG on its own 13

200

150

100

50

0

0 200 400

t / min

Figure 10 Comparison of bubble radius R as a function of time t for bubbles stabilized by
colloidal silica + DDAB or b -LG at pH ¼ 7: ' , 0.5 wt% silica + 8 10 4
mol dm 3 DDAB; E , 1 wt% silica + 0.05 wt% b -LG 13

200

150

100

50

0

0 200 400

t / min

Figure 11 Comparison of bubble radius R as a function of time t for bubbles stabilized by
0.05 wt% b -LG at pH 7 + different silica particles: ' , 1 wt% colloidal silica;
E , 1 wt% fumed silica. The solid lines above indicate the expected behaviour of
0.05 wt% b-LG on its own 13

In Figure 11 the effect of silica particle size is presented, where the time-
dependent radii for bubbles stabilized by 5.5-nm (colloidal) and 20-nm (fumed)
silica are compared. The behaviour of a bubble stabilized by pure b-LG is also
represented. It is obvious that the smaller colloidal silica particles can enhance
the lifetime of the bubbles to a much greater extent than does the fumed silica.