A simple, versatile, rapid, and inexpensive procedure based on the immersion method is developed to fabricate chemical gradients on chemically activated Si/SiO2 surfaces by a trichloro (1H,1H,2H,2H-perfluorooctyl) silane self-assembly monolayer (SAM). Contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy data based on the intensity of the signals of C1s and F1s, which progressively increase, indicate that the surface is characterized by the presence of increasing amounts of the SAM along the gradient direction. Experimental conditions are optimized by maximizing the variation of the contact angle of water drops at the starting and the ending points of the gradient. The application of the chemical gradient to droplet motion is demonstrated. The results are rationalized by dissipative particle dynamics simulations that well match the observed contact angles and the velocities of the drops. The simulations also show that the intrinsic nature of the gradient affects the velocity of the motion.

And Yet it Moves! Microfluidics Without Channels and Troughs

FIORAVANTI, GIULIA;
2013-01-01

Abstract

A simple, versatile, rapid, and inexpensive procedure based on the immersion method is developed to fabricate chemical gradients on chemically activated Si/SiO2 surfaces by a trichloro (1H,1H,2H,2H-perfluorooctyl) silane self-assembly monolayer (SAM). Contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy data based on the intensity of the signals of C1s and F1s, which progressively increase, indicate that the surface is characterized by the presence of increasing amounts of the SAM along the gradient direction. Experimental conditions are optimized by maximizing the variation of the contact angle of water drops at the starting and the ending points of the gradient. The application of the chemical gradient to droplet motion is demonstrated. The results are rationalized by dissipative particle dynamics simulations that well match the observed contact angles and the velocities of the drops. The simulations also show that the intrinsic nature of the gradient affects the velocity of the motion.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/16254
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 22
  • ???jsp.display-item.citation.isi??? 21
social impact