Microparticle synthesis and characterization
PFC-MPs were synthesized using a T-shaped polydimethylsiloxane (PDMS)
droplet generator as previously described.[16]Briefly, using oil (span80, Sigma Aldrich, cat#
1338-43-8)
as a continuous phase in the two side channels and polymer solution as
the dispersed phase in the middle channel, we produced a steady stream
of homogenous PFC- MPs. These MPs were passed through a glass tube and
polymerized using the photoinitiator Lithium
phenyl-2,4,6-trimethylbenzoylphosphinate (LAP,0.1wt% in distilled
water, Sigma-Aldrich, cat#
85073-19-4)
included in the polymer phase, under the irradiation of a lamp (600-700
nm). The composition of MPs was characterized via X-ray photoelectron
spectroscopy (XPS) with a scanning monochromated Al Kα (117.40 eV;
25.0 W; spot size, 100 μm). The take-off angle between the sample
surface and analyzer was 45.0°, and the X-ray beam collected C1s, N1s,
F1s, and O1s elemental information. We also tested the MPs using
thermogravimetric analysis (TGA) to study their thermal stability. 5 mg
of PFC- MPs were weighed and placed in an open pan (platinum 100 µL)
attached to a microbalance (TGA550, TA Instruments). The sample was
heated at 10 °C.min-1 from 25 to 700 °C under dry
nitrogen in standard mode with a ramp test type.