# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
Supplemental info for “Novel alignment technique for LCD-biosensors”
Additional Experimental techniques:
The PI-ITO plate with the drop of buffer is placed in a Petri dish, after which a pipette is used
to blow the drop from one end of the substrate to the other under an angle of 45 ° (see: Li et
al, Nucleic Acids Research, 1998, 26(20), 4785-4786). The nitrogen flow is adjusted so that
the drop traverses the 1,5 cm long plate in about 5 seconds. After the drop has reached the far
side of the plate, the Petri dish is turned 180 degrees and the process is repeated until the drop
has dried.
Twisted-nematic LCD with a directionally dried TE-covered plate (direction of blowing: topbottom), with a PI-counter plate rubbed in the left-right direction (as indicated by the arrow).
The image on the left is viewed between crossed polarisers, the one on the right between
parallel polarisers. The anchoring energy between the TE-layer and the LC is not sufficiently
high to disrupt LC-ordering induced by the PI-plate. Image is 1,0 X 0,8 cm.
AFM (left) and SEM (right) images of a TE-covered PI-ITO plate made by directional drying.
The arrow indicates the direction of blowing. The AFM image is 3 X 2.5 m, the bar in the
SEM image is 100 nm.
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
SEM image of DNA on TE-buffer layer
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
FT-IR spectra
Note: directional drying was maintained for the indicated times.
95.2
90
85
80
75
%T
70
65
3335.24
60
3188.67
55
50
45.4
3336.21
3601.5
3400
3200
3000
2800
2600
2487.1
cm-1
OH- and NH-region of a directionally dried TE-buffer in H2O.
Determining the exact water content for the transition observed in these experiments (by
weighing) proved difficult, gave irreproducible results and was not attempted further.
Black: 5 minutes, blue: 10 minutes, red: 15 minutes.
102.5
100
95
90
85
1296.26
80
%T
75
1057.48
1038.25
70
65
60
1059.94
55
53.0
1299.5
1250
1200
1150
1100
1050
cm-1
1000
950
Ether-region (C-O and C-N) of a directionally dried TE-buffer in H2O.
Black: 5 minutes, blue: 10 minutes, red: 15 minutes.
900
850
809.2
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
106.4
100
95
1518.25
1655.16
1648.97
1284.74
90
1502.97 1477.83
%T
1546.84
1513.39
1535.28 1529.45
1624.90
85
1618.14
1358.94 1334.27
1439.11
1421.07
1467.72
1365.74
1407.47
1296.26
1447.47
1496.50
1489.72 1464.00 1435.99
1472.29
1516.16
1457.01
1417.98
80
1646.56
1616.01
1533.01
1568.99
75
1652.94
1627.081622.90
1575.85
1634.83
69.5
1673.5 1650
1600
1339.56
1521.05
1540.00
1558.63
1550
1506.95
1394.93 1386.97 1373.95
1500
1450
cm-1
1400
1350
1362.38
1300
1238.0
Carbonyl region of directionally dried TE-buffer in H2O (red) and D2O (blue). Drying time
both 15 minutes.
Key shifts induced by the change of the solvent:
1540.00→1535.28
1533.01→1529.45
1521.05→1518.25
1516.16→1513.39
1506.95→1502.97
93.1
90
85
80
2943.19
2889.40
75
%T
70
65
3338.02
2978.58
2943.60
60
3188.67
55.9
3645.8
3400
3200
3000
2800
2600
cm-1
OH- and NH-region of directionally dried TE-buffer in H2O (red) and D2O (blue). Drying
time both 15 minutes.
2450.2
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
16.5
1733.81
14
12
10
1436.51
8
Egy
1418.93
1670.22
1733.70
1716.94
6
1497.21
1497.12
1576.62
1716.72
1698.91
1684.20
1617.19
4
1698.77
1473.58
1457.38
1489.93
1521.50
1521.54
1635.97
1507.64
1558.62
1684.22
2
1436.99
1489.87
1507.65
1576.33
1670.24
1473.49
1458.18
1541.25
1652.95
1418.84
1403.51
1634.70
0
1555.14
-1.0
1747.8
1700
1650
1600
1550
1500
1450
1399.1
cm-1
Carbonyl region of a directionally dried TE-buffer from H2O (black, drying time 15 minutes)
and a mixture of equimolar amounts of solid Tris-EDTA which was ground in a mortar (red).
OH- and NH-region of a directionally (blue) and non-directionally (purple) dried drop of TEbuffer on a PI-ITO plate.
# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
Directional drying of a 10 mM Urea solution
Parallel LCDs made by directional blowing of a 10mM Urea solution show partial LC
alignment (right image).
Note on the stability of the alignment layer
The observation that the alignment is lost after seven days can be explained in different ways.
Two likely possibilities are:
1) The buffer gradually dissolves in 5CB over time. Experiments show that the same
amount of buffer present on the surface can be dissolved in 1 ml of 5CB by sonicating
at room temperature for 30 minutes.
2) The surface ordering is gradually lost by the thermal reshuffling of the hydrogen bond
network, also possibly involving interactions with the cyano-group of the LC: SEM
experiments showed that the surface order disappears within seven days, resulting in a
featureless surface.”