Biomedical Engineering Reference
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spin-coated (Laurell Technologies model WS-400A-6NPP) by depositing 50-100
lon
the PVAm-modified substrates at 5000 rpm for 40 seconds. We found these conditions
as optimal for obtaining robust, smooth films. The cellulose-coated substrates were
removed from the coater and then immersed in water during four hours and placed
in an oven for two hours at 80
◦
C. The substrates were then washed thoroughly with
water, dried with a nitrogen jet and stored at room temperature in a clean chamber for
further use. An AFM image of the obtained films as well as a typical height profile
are shown in Figure 4.4. Because of the chemical homogeneity and flat topography
such thin films of cellulose are useful as platform for nanoscale studies that involve
Surface Plasmon Resonance, Quartz Crystal Microbalance as well as Lateral Force
Microscopy.
µ
µ
m
4.5
8
4.0
7
6
3.5
5
3.0
4
2.5
3
2.0
2
1.5
1
1.0
0
0.5
0
1.0
2.0
3.0
4.0
µ
m
(a)
(b)
µ
m
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1.0
2.0
3.0
4.0
µ
m
(c)
Figure4.4
5
5
µ
mnon-contactmodeAFMheight (a),correspondingsectionanalysis(b),
andphase (c) images of cellulose thinfilmona silicawafer. Thefilmis about 20nmthick
(obtainedbyellipsometry)withanRMSroughnessof ca. 2nm.
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