Simultaneous Fabrication of Superhydrophobic and Superhydrophilic Polyimide Surfaces with Low Hysteresis

Abstract

Polyimide is of great interest in the field of MEMS and microtechnology. It is often used for its chemical, thermal, mechanical, and optical properties. In this paper, an original study is performed on controlled variation of polyimide film wettability. A two-step microtexturing method is developed to transform hydrophilic polyimide surfaces into a superhydrophobic surface with low magnitude of hysteresis (Δθ ≈ 0° and contact angle θ ≈ 158°). This method is based on the conception of a new kind of fakir surface with triangular cross-section micropillars, the use of a two-scale roughening, and a C(4)F(8) coating. We demonstrate that the absence of hysteresis is related to a combination of two scales of structuring and the pillar shape. The technology that has been developed results in the simultaneous fabrication of adjacent superhydrophobic and superhydrophilic small areas, which allows an effect of self-positioning of water droplets when deposited on such a checkerboard-like surface.

Preparation of superhydrophobic polyimide films modified with organosilicasol as effective anticorrosion coatings

“…Although many approaches have been developed for the fabrication of superhydrophobic surfaces, including electrospinning [6], etching [7], plasma treatment [8,9], chemical vapor deposition (CVD) [10,11], addition of a sublimation material [12,13], molding [14,15], electrodeposition [16], and sol-gel processing [17][18][19][20], the modification techniques to create rough structures on PI surfaces remain a challenge. Recently, nanoparticles (NPs) have become popular modifying agents for controlling surface roughness [21].…”

Poling Field Dependence of Longitudinal and Transverse Wave Velocities, Young's Modulus, and Poisson's Ratio in Piezoelectric Ceramics

“…Within the 'more than Moore' trend, which aims at enhancing the capabilities of current microelectronics devices [1], polymers are increasingly used in the semiconductor industry as enabling materials for building or for the active layer in microsystems [2], with specific applications in molding [3][4][5], microfluidics [6] and sensing applications [7]. a low residual stress level of around 2 MPa in a 10 μm thick film, and a Young's modulus of about 8.5 GPa, see e.g.…”

Laser surface modification of polyethersulfone films: effect of laser wavelength on biocompatibility

“…Increasing the surface roughness at a fluence of the 70 mJ/cm 2 increases the number of adhered cells to the surface. [11]. Regardless of the absorption of the surface at the laser wavelength, Irradiation of PES surface at the fluences below the ablation threshold, leads to increasing the surface hydrophilicity and biocompatibility especially for the decreasing the platelet adhesion in the blood contact works.…”