Kapton polyimide film

A serpentine-patterned LIG (Figure 7) was fabricated directly onto a commercial PI film (125 μm-thick Kapton polyimide film, DuPont, Wilmington, DE, USA) with a CO₂ laser system platform (VLS 2.30DT, power P_max = 30 W, speed S_max = 1270 mm·s⁻¹, and wavelength λ = 10.6 μm, Universal Laser Systems, Scottsdale, AZ, USA). The two circle shapes on the LIG were formed on each top and bottom edge to provide electrical connections. The optimized laser parameters were a laser power of 4 W, a scanning speed of 127 mm·s⁻¹, and an image density of 500 pulses per inch (PPI, 1 inch = 25.4 mm); these parameters were used for fabricating all of the devices. The desired pattern was designed via AutoCAD and CorelDRAW.

Thin sections (50–70 μm-thick) were obtained from fully developed, de-husked rice grains of the different genotypes using a vibrating blade microtome (VT1000 S, Leica Microsystems GmbH, Wetzlar, Germany), following the protocol described by Johnson et al. (2011) (link). Seeds were glued (with Loctite Super Glue-3, Barcelona, Spain) to the excised bottom of a 1.5 mL plastic Eppendorf tube, and blades used were Chrome Platinum (Bic, Clichy, France). Vibratome parameters were a blade movement speed of 0.2 mm s^-1 and a vibration frequency of 70 Hz. A 100 μm-thick Kapton polyimide film (DuPont, Des Moines, IA, United States) was used to hold the tissue section as cutting proceeded, to minimize endosperm fragmentation (Johnson et al., 2011 (link)). Longitudinal dorso-ventral seed sections were used for optical microscopy, Perl’s staining and LA-ICP-MS analysis. Sections were transferred to synchrotron adhesive tape (Leica), attached to glass slides, observed with a stereomicroscope (MZ16, Leica) and images taken with the Leica Application Suite V3.5. Sections were stored at 4°C until LA-ICP-MS analysis.

The diF-TES-ADT:PS_10K (4:1) and PDI8CN2:PS_280K (1:2) blend solutions
used in this work were prepared according to our previously published
protocol.^{15 (link),29 (link)} The S/D electrodes (Cr/Au, 5/40 nm), with a geometrical ratio W/L = 690 (channel width W = 20 700
μm and channel length L = 30 μm), were
deposited on Kapton polyimide film (75 μm thick, DuPont) by
a thermal evaporation system (Evaporation System Auto 306 from Boc
Edwards) at a pressure of 2 × 10^–4 Pa. Prior
to the deposition of the OSC:PS blend solution, the S/D substrates were cleaned in an ultrasonic bath
with acetone and isopropanol for 15 min each, followed by an ozone
treatment for 25 min. After that, the cleaned S/D electrodes were functionalized by PFBT through immersion
of the substrate into PFBT/isopropanol (2 μL:1 mL) solution
for 15 min and then rinsed with isopropanol. Finally, all of the OSC:PS
blend films were coated by the bar-assisted meniscus shearing (BAMS)
technique at a fixed speed of 1 cm·s^–1 and
a plate temperature of 105 °C in ambient conditions as previously
reported.^{15 (link)}