Extended Data Fig. 2: Importance of contact angle of PET belt and biochip.
From: Fast, cost-effective and flexible DNA sequencing by roll-to-roll fluidics
a, Plasma treatment generates hydrophilic moieties. b, Raman spectra before and after plasma treatment showing an increased O-H vibration. c, List of surface tensions of the different reagents and wash buffers. d, Hand-drawn straight lines using an Arcotest pen with 36 mN/m ink on the biochip, which immediately beads up and indicates poor wetting, while on the PET belt lines with 36, 38 and 42 mN/m ink remain continuous, whereas those with higher surface energies, 46 and 50 mN/m, bead up. The biochip surface is fabricated with a matrix of hydrophilic nanowells surrounded by hydrophobic HMDS (hexamethyldisilane), resulting in an overall poor-wetting surface. e, Contact angle measurements of water and wash buffer 2 on the treated biochip and PET surfaces.
