International Journal of Physical Sciences Vol. 3 (6), pp. 144-147, June, 2008
Available online at http://www.academicjournals.org/IJPS
ISSN 1992–1950 © 2008 Academic Journals
Full Length Research Paper
Study on the morphology of polyacrylamide – silica
fumed nanocomposite thin films
Mukhles Sowwan
1
, Maryam Faroun
1
, Ishaq Musa
1
, Imad Ibrahim
1
, Sami Makharza
1
, Wadie
Sultan
2
and Hasan Dweik
2
1
The Nanotechnology Research laboratory, Materials Engineering Department, Al-Quds University, East Jerusalem-
Palestine.
2
Department of Chemistry, Al-Quds University, East Jerusalem-Palestine.
Accepted 28 May, 2008
Silica fumed nanoparticles were dispersed in polyacrylamide thin films by direct mixing. Atomic Force
Microscopy study was carried out in order to analyze the surface roughness. Height distribution of
surface roughness changes from Gaussian like for polyacrylamide to skew asymmetric when
increasing the silica concentration. The length of the distribution tail increases, indicating the
formation of multi-scale features that increase in number and size, as the silica increase.
Key words: Polyacrylamide, nanocompsite, surface roughness, AFM.
INTRODUCTION
In recent years, polymeric nanocomposites gained in-
creasing attention in wide range of industrial applica-tions
including coatings, electronics, and adhesives (Alexandre
and Dubois, 2000; Tsukruk et al., 2002; Karttunen et al.,
2008). If properly dispersed, fillers such as silica nano-
particles can substantially improve the physical proper-
ties of the resulting nanocomposites with respect to mi-
crocomposites containing the same amount of filler; the
reason for the improvement is the higher inter-facial area
between the polymer matrix and filler in the nanocom-
posite than in micro-composite, (Alexandre and Dubois,
2000; Lan and Pinnavaia, 1994). But also fillers change
the surface morphology and nanoscale rough-ness of the
polymer films leading to change in its optical, physical
and chemical properties (Richard and Malhotra, 2006;
Tjong 2006). Consequently, techniques with high sensiti-
vity to the surface physical and chemical properties are
required to reveal the nanoscale properties of nano-com-
posites. Atomic Force Microscopy (AFM) is a powerful
technique that can provide direct spatial mapping of sur-
face topography with nanometer resolution (Cleveland et
al., 1998). Tapping mode AFM, for example, often re-
flects differences in the properties of individual compo-
nents of heterogeneous materials deposited on surface,
*Corresponding authors. E-mail: msowwan@eng.alquds.edu
and is useful for roughness measure-ments and composi-
tional mapping of polymer nanocom-posites, copolymers,
and coatings. (Raghavan et al., 2000; Raghavan et al.,
2001; Gu et al., 2001; Bar et al., 1997; Frisbie et al.,
1994). In the present work, the surface morphology and
nanoscale roughness of a polymer nanocomposite thin
films, namely silica fumed-polyacr-ylamide nanocompo-
site used for coating capillary tubes (Alejandro and Jose
1998), prepared by thin film replication method (Sowwan
et al., 2008) were studied using AFM.
MATERIALS AND METHODS
Materials
Polyacrylamide (PAam) with Mw 5,000,000 and silica fumed 7nm in
diameter were purchased from Sigma-Aldrich Co. and used as
received. All solutions were prepared in triple distilled water.
Mica sheets (V-5 grade) substrates were purchased from SPI
suppliers Co, USA. Glass microscopic slides were purchased from
Paul Marienfeld GmbH &Co, Germ. Optical grade silicon window
(Nicodom Ltd.).
Instruments
FTIR spectroscopy measurements were performed using a
BRUKER IFS66/S spectrophotometer .A scanning atomic force mi-
microscope and software designed by Nanotech Electronica com-
pany (Madrid , Spain) were used for the surface roughness
investigation (Horcas et al., 2007). A SiN tip with a resonance fre-