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.com
RRJOMS | Volume 5 | Issue 4 | July, 2017
July 27-29, 2017 Vancouver, Canada
10
th
International Conference on
Emerging Materials and Nanotechnology
Res. Rev. J Mat. Sci. 2017
DOI: 10.4172/2321-6212-C1-003
The synthesis of PNIPAAM-coated thermoresponsive textile via emulsion polymerization
Songmin Shang
and
Ka Lok Chiu
Hong Kong Polytechnic University, Hong Kong
A
series of semi-interpenetrating polymer network (semi-IPN) hydrogel based on poly (vinyl alcohol) (PVA) and poly
(N-isopropylacrylamide) (PNIPAAm) were prepared by emulsion polymerization. There were 5 samples composed of
different amount of initiators and catalysts for emulsion polymerization. The changes of particle sizes of each hydrogel were
monitored at temperatures 30
o
C, 35
o
C 40
o
C and 45
o
C respectively. The optimal hydrogel was coated onto cotton fabrics and
then the coated fabrics were investigated by swelling experiment, scanning electron microscope (SEM) and Fourier transform
infrared (FTIR) spectroscopy. The thermo-behavior of the semi-IPN hydrogel is observed. Experimental data indicates the
amount of initiators and catalysts added is an influential factor for the formation of optimal hydrogels while the concentration
of hydrogel is not. The coated fabric is able to change the swelling ratio by 10.1% at the Lower Critical Solution Temperature
(~35
o
C), whichmeans the fabric is sensitive to the change of temperature. SEMresults indicate that the semi-IPNhydrogel affects
the surface appearance of the cotton fabric. Further confirmation of chemical structure is completed by FTIR spectroscopy.
shang.songmin@polyu.edu.hkEnhanced photocatalytic activity of La
3+
and Se
4+
co-doped bismuth ferrites nanostructures
Syed Irfan
Tsinghua University Beijing, China
P
hotocatalysis is attracting huge interest by addressing current energy and environmental issues by converting solar light
into chemical energy. For this purpose, we investigated the effect of La
3+
and Se
4+
co-doping on photocatalytic activity of
BiFeO
3
. The BiFeO
3
and Bi
0.92
La
0.08
FeO
3
nanoparticles containing different Se
4+
doping contents (BiFe
(1-x)
Se
x
O
3
,x= 0.0, 0.02,
0.05) and (Bi
0.92
La
0.08
Fe
(1-x)
Se
x
O
3
, x = 0.0, 0.02, 0.05, 0.075, 0.1), respectively, were synthesized with double solvent sol-gel route.
The co-doped nanoparticles were characterized by X-ray diffractometry (XRD), field emission scanning electron microscopy
(FESEM), high resolution transmission electron microscopy (HRTEM), and UV-Vis diffuse reflectance spectroscopy (DRS),
and their photocatalytic activity was studied by photocatalytic degradation of Congo red (CR) in aqueous solution under
different wavelengths of light illumination. The band-gap of the pure BiFeO
3
was significantly decreased from 2.06 eV to 1.94
eV. It was found that the La
3+
and Se
4+
co-doping significantly affected the photocatalytic performance of pure BiFeO
3
. Moreover,
with the increment of Se
4+
doping into Bi
0.92
La
0.08
FeO
3
up to an optimal value, the photocatalytic activity was maximized. In
order to study the photosensitization process, photo-degradation of colorless organic compound (acetophenone) was also
observed. On the basis of these experimental results, the enhanced photocatalytic activities of La
3+
and Se
4+
co-doping could be
attributed to the increased optical absorption, the efficient separation and migration of photo-generated charge carriers with
the decreased recombination of electron-hole resulting from co-doping effect. The possible photocatalytic mechanism of La
3+
and Se
4+
co-doped BiFeO
3
was critically discussed
irfansyed715@gmail.com