Ultrathin Fluidic Laminates for Large‐Area Façade Integration and Smart Windows

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Adv.
Sci. 
2016
, 1600362
Figure 8. 
Flow velocity distribution within the microfl uidic device. Regions with a velocity magnitude higher or equal to 10 mm s 
−
1
are colored in dark red.
Figure 9. 
Computational rendering of an experimental façade implementing fl uidic window devices as reported here. A) Indoor by day. 
B) Outdoor by night (see text for details).

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2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.MaterialsViews.com
Adv.
Sci.
2016
, 1600362
www.advancedscience.com
quality, high transparency, and high mechanical stability. 
[ 49 ]
Relevant 
properties of this glass are its transition temperature
T
g
of 525 
°
C, a 
coeffi cient of linear thermal expansion
α
(20–300 
°
C)
of 3.25 
×
10 
−
6
K 
−
1
, and 
a thermal conductivity
λ
(90 
°
C)
of 1.2 W m 
−
1
K 
−
1
. 
[ 50 ]
Its UV absorption 
edge lies at 275 nm. We used a 5 mm glass sheet into which an array 
of 32 trapezoidal channels was milled, and a 0.7 mm cover glass sheet 
( 
Figure
10
). Both glasses were bonded together with a robot-printed 
UV-curing acrylate (Delo-Photobond GB368, DELO Industrial Adhesives), 
whereby bonding was facilitated through the high UV transparency of 
the employed type of glass. The selected adhesive was applied at a feed 
rate of 5 mm s 
−
1
and a pressure of 5 bar by means of a
xy
-displaceable 
dispenser unit (Fisnar 7400C, I&J Fisnar, USA) equipped with a dosing 
syringe with a needle diameter of 0.25 mm. Curing was performed with 
UV light (Delolux LED curing lamp, DELO Industrial Adhesives) at 
a wavelength of 400 nm. The device was exposed during 120 s at an 
UV-A intensity of 100 mW cm 
−
2
. The employed adhesive is optically 
transparent across the visible spectral range with a refractive index of 
1.506. 
[ 51 ]
Its Young’s modulus is 900 MPa and the thermal expansion 
coeffi cient in the temperature range of 25–140 
°
C is 236 ppm K 
−
1
. 
[ 51 ]
The cured adhesive has a high temperature resistance, reportedly across 
the temperature range from 
−
40 to 
+
120 
°
C. 
[ 51 ]
The cross-section of an as-machined capillary is shown in Figure 10 B, 
and of the bonded system in Figure 10 C. The characteristic dimensions 
of the capillaries as determined by optical microscopy after machining