Supporting Information
Thermosensitive Hollow Janus Dumbbells
Fangfang Chu,1 Frank Polzer,2 Nikolai Severin,2 Yan Lu,1* Andreas Ott,1 Jürgen P. Rabe,2 Matthias
Ballauff 1,2*
1
Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, HahnMeitner-Platz 1, 14109 Berlin, Germany
2
Department of Physics, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany
Experimental details
PS spheres: The synthesis of PS spherical seeds was performed in a 1 L three-necked glass flask
through conventional emulsion polymerization. First, 0.42g SDS was firstly dissolved in 275 mL water
under stirring at 200 rpm, which was controlled by a mechanical stirrer (EUROSTAR). Next, 30g styrene was charged into the reactor under stirring. After a complete mixture (stirring for 20 minutes), 0.3g
KPS dissolved in 25 mL H2O was added into the mixture. The reaction was done under nitrogen atmosphere and the temperature was controlled at 70 °C.
PS-MPS spheres: Using spherical PS seeds, a copolymer layer of styrene and MPS was coated onto the
surface of PS seeds via the seeded emulsion polymerization, which aimed to facilitate the growth of the
second sphere for the dumbbell-shaped cores. The core-shell PS spheres are referred as PS-MPS
spheres. During this step, 166.8 g of PS latex with (solid content: 7.94 wt.-%) was diluted with 50 mL
H2O in a 1 L three-necked glass flask that was used as the reactor. Then 1.25 g MPS and 0.08g AIBN
were dissolved in 12.53 g styrene, which was charged into the reactor under stirring at 250 rpm. 20
minutes later, the reaction was started by increasing the temperature to 70 °C under nitrogen atmosphere. 8 hours later, the reaction was finished and the latex was cooled to the room temperature.
Dumbbell-shaped core: In this step, a 500 mL three-necked glass flask as the reactor, 61.5 g
H2Odissolving 0.45 g NaSS was mixed with 138.5 g of 7.78wt.-% PS-MPS latex under stirring at 200
rpm. After 20 minutes, 0.18 g AIBN dissolved in 32.91 g styrene was charged into the reactor, which
would swell into the PS-MPS spherical particles. The reaction was started by increasing the temperature
to 70 °C under nitrogen atmosphere. The reaction lasted for 8 hours. In the end, the homogeneous
dumbbell-shaped PS cores were obtained and purified by dialysis for 3 days with water.
Dumbbell-shaped microgels: In a typical run, a 2L three-necked glass flask served as the reactor, where
150.6 g of 7.13wt.-% PS core latex was mixed with 145 g water containing a mixture of NIPA and BIS
monomers. After a complete mixture (stirring for ca. 20 minutes), 0.3 g KPS dissolved in 5 g H2O was
charged into the reactor under nitrogen atmosphere. The reaction started by increasing the temperature
to 80 °C, and ran for 4.50 hours. Afterwards, the dumbbell-shaped microgels were cleaned by ultrafiltration for around one month.
S1
Figure S1 TEM image of dumbbell shaped PS core particles.
Figure S2. TEM images of dumbbell core particles dissolved in THF after the first cycle of cleaning (a)
and after the final cleaning procedure (more than 10 cycles of cleaning) (b). As marked by the red arrow
in (a), the dissolved PS are distributed inside and outside the copolymer spheres after the first cleaning
cycle of the dumbbell-shaped core particles via THF.
S2
20°
30°
Intensity
1.5
1.0
0.5
0
0.1
10
Lag time [ms]
1000
Figure S3. The correlation functions of the Janus hollow dumbbells that are measured at the scattering
angle of 20° (solid line) and 30° (dashed line) under the temperature of 20 °C.
REFERENCES
1. Forster, J. D.; Park, J.-G.; Mittal, M.; Noh, H.; Schreck, C. F.; O’Hern, C. S.; Cao, H.; Furst, E. M.;
Dufresne, E. R. ACS Nano 2011, 5, 6695.
2. Chu, F. F.; Siebenburger, M.; Polzer, F.; Stolze, C.; Kaiser, J.; Hoffmann, M.; Heptner, N.; Dzubiella,
J.; Drechsler, M.; Lu, Y.; Ballauff, M. Macromolecular Rapid Communications 2012, 33, 1042.
S3