Wetting properties of flat and porous silicon surfaces coated with a spiropyran.
We report the immobilization and characterization of a spiropyran (SP) derivative (1) on smooth Si(100) and porous H-terminated silicon surfaces through a thermal hydrosilylation protocol. Under visible light exposure the SP is in a closed, hydrophobic form, whereas under UV irradiation it converts to a polar, hydrophilic open form named merocyanine (MC). The SP-MC photoinduced isomerization gives a small contact angle (CA) change of 9 degrees for smooth Si(100) samples under sequential irradiation cycles with white and UV light. Irradiation of porous silicon (PS) surfaces, under the same conditions, gave a CA change of 11 degrees. Treatment of PS surfaces, bearing the MC form of chromophore 1, with cobalt(II) ions enhances the wettability switching of the PS surface to a much larger extent, giving rise to a CA variation as high as 32 degrees.
Dattilo
Davide
D
Dipartimento di Scienze Chimiche, INSTM and ISTM-CNR, Università di Padova, Via Marzolo 1, 35131 Padova, Italy.
Armelao
Lidia
L
Fois
Giovanni
G
Mistura
Giampaolo
G
Maggini
Michele
M
D001578:Benzopyrans / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D009574:Nitro Compounds / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014466:Ultraviolet Rays
D001578:Benzopyrans; D007211:Indoles; D009574:Nitro Compounds; C088184:spiropyran; D012825:Silicon