Fig. 3. Images of the pure polypropylene microfluidic chip: (A) An image of the microfluidic chip with stainless steel pipes and microchannels obtained at the angle of ∼90° between the incident light (illuminating the microfluidic chip) and the optical axis of the camera lens. (B) The image of the cross-section of the microchannel obtained by an optical microscope. (C) An SEM image of the microchannel's cross-section. The cross-sections were obtained by blade cutting.
