Supporting Information
A single glass fiber with ultrathin layer of carbon nanotube
networks beneficial to in-situ monitoring of polymer
properties in composite interphases
Jie Zhangab, Rongchuan Zhuangc, Jianwen Liua, Christina Schefflera, Edith Mädera*,
Gert Heinricha, Shanglin Gaoa*
a
Leibniz - Institut für Polymerforschung Dresden e.V. Hohe Strasse 6, 01069
Dresden, Germany
b
Electronic Materials Research Laboratory, Key Laboratory of the Ministry of
Education & International Center for Dielectric Research, Xi’an Jiaotong University,
710049 Xi’an, P. R. China
c
Xiamen Zijin Mining and Metallurgy Technology Co. Ltd. 361101 Xiamen, P. R.
China
EXPERIMENTAL SECTION
Depositing MWNTs onto glass fibre
The alkali-resistant (AR) glass fibres with an average diameter of 12 μm were
manufactured without sizing in our institute. Commercially available carboxy
functionalized MWNTs (NC3101, Nanocyl S.A., Belgium) with an average diameter
of 9.5 nm and an average length of 1.5 μm were used. Using non-ionic surfactant
1
Igepal CO 970 (nonylphenol ethoxylate) from Rhodia Germany, a stable surfactant
solution (pH 6-7) with a concentration of 0.05 wt. % of MWNTs was prepared. The
dispersed MWNTs were deposited onto the surface of glass fibre through
electrophoretic deposition (EPD), at constant voltages 4.5 V for 10 min.1,2 The glass
fibre can not be used as electrode directly, due to its insulating property. Instead, we
used two parallel copper plates with rectangular-shape (7cm×2.5cm×0.1cm) as
cathode and anode. According to streaming potential results, the dispersed MWNTs
and the hydrolyzed Glymo showed negative charge and migrated toward the positive
electrode, the anode was used as deposition electrode, glass fibres were fixed on a thin
plastic frame, and then the frame was mounted on the anode. The coated MWNTsglass fibres were dried at 40 °C in a vacuum oven for 8 h, the mass increase was about
1.0 wt% and the roughly estimated numbers of MWNTs per µm2 surface area of glass
fiber are 300~500.
Simultaneous measurement of electrical resistance with polymer change
Two thin coverslips sputter-coated with Au were adhered to a glass slide as
electrodes, the gap between two electrodes was 5 mm, and then two conductive wires
were connected to two electrodes using silver paste (Acheson Silver DAG 1415M),
respectively. The ends of single MWNTs-glass fibers were mounted onto electrodes
with silver paste, and then the whole glass slide was put on a hot-stage (Linkam
LTS350 Heating/Freezing, UK) in a nitrogen atmosphere. An epoxy mixture was
dropped or PET film was put onto the fibre surface, then the hot-stage was sealed.
Two conductive wires were connected to the Keithley 2000 multimeter with constant
2
test current (10 µA / 700 nA), and the direct electric (DC) resistance was recorded as
the output signal.
DSC measurement
The polymerization and crystallization were investigated by modulated differential
scanning calorimetry (Q2000 MDSC, TA Instruments, USA). DSC was conducted at
the same heating and cooling rate with electrical measurement in order to compare the
different results. From the results of the DSC experiments, the governing equations to
calculate the degree of conversion during isothermal cure β of thermosetting resin
were determined as follow: 3
d
dt
( 1
HT
)( dQ )
dt
where dQ/dt is the instantaneous rate of generated heat; HT is total heat generated in
the isothermal scanning of DSC.
Infrared analysis
Fourier transform infrared spectroscopy (FTIR) was performed using a Fourier
transform infrared spectrometer (Equinox 55, Bruker) equipped with a temperaturecontrolled cell which was continuously purged with nitrogen gas. A series of spectra
on epoxy mixers sandwiched between two potassium bromide (KBr) pellets was
obtained at each cure temperature, which ranged from ambient temperature to 200 oC,
at rate of 3 K/min. Each spectrum from 4000 to 600 cm-1 was averaged over 32 scans
3
taken, at 2 cm-1 resolution. The epoxy functional group absorbance peak,
υEP = 915
cm-1. The nomalized relative area, p of a functional group versus temperature is
calculated by:
p
Atemp
A27
where A is the area of the epoxy group’s absorbance at various temperatures (shown
in Figure S1), subscripts “temp” refer to the various temperatures.
Figure S1 The absorbance of epoxy functional group at various temperatures during
dynamic curing process.
References
4
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2010, 48, 2273-2281.
(2) Zhang, J.; Liu, J. W.; Zhuang, R. C.; Maeder, E.; Heinrich, G.; Gao, S. L. Adv.
Mater 2011, 23, 3392-3397.
(3) Kim, H. G.; Lee. D. G. Compos. Struct. 2002, 57, 91-99.
(4) Warfield, R. W.; Petree, M. C. Polym. Eng. Sci. 1961, 1, 80.
(5) Simon, S. L.; Gillham, J. K. J. Appl. Polym. Sci. 1992, 46, 1245-1270.
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