Plasma codeposition of transparent thin films: Relationship between the surface chemistry and the anti‐fogging property

Abstract

Anti‐fogging coatings are deposited on the polycarbonate thanks to the low pressure pulsed plasma. Two precursors are simultaneously polymerized: One contains hydrophilic groups (2‐(dimethylamino)ethyl methacrylate or acrylic acid [AA]) whereas the other one (1 H,1 H,2H‐perfluoro‐1‐decene [HDFD]) is hydrophobic. Several proportions of (HDFD) are applied to prepare films with high hexadecane (≈70°) and low water (≤20°) contact angles. Evidence of their hydrophilic, oleophobic properties is given by the wettabillity and the anti‐fogging measurements. It appears that all plasma‐codeposits issued from AA and HDFD with high hexadecane contact angle are more oleophobic than the plasma‐copolymers 2‐(dimethylamino)ethyl methacrylate and HDFD, irrespective of the proportion of the fluorinated precursor. Such a behavior is explained by the grafting of longer perfluorinated chains. The anti‐fogging properties are not directly correlated to the wettability. Moreover, the films act as predicted by the flip flop mechanism.

Characterization of surface physico-chemistry and morphology of plasma-sized carbon fiber

“…Excepted ppAA / CF n° 2, 4 and 5 (Fig. 10), the surface free energy (SFE) of most of the plasma-polymers are similar and around value of 22 mJ/m², lower that the untreated fibre one's previous works [31,45]. Indeed, above FTIR spectra of the different plasma-polymers showed significant traces of oxidation of the thin films.…”

“…The deposition of the ppHMDSO, as for also the other precursors is operated in mildest conditions preserving the HMDSO chemical structure [45]. Such deposited layer is characterized by FTIR spectroscopy (Fig.…”

Role of the surface chemistry of plasma polymer layers on their long‐term antifogging behavior

“…Even if the different observed behaviors of wettability and surface chemistry for these aged layers are related to the different analyzed thicknesses (first monolayer with contact angle and 10–20 nm with XPS), these analyses support the idea that chain motion may play a major role in aging resistance as observed for the antifogging property explained by the so‐called “flip flop mechanism”. [ 38 ] Indeed, the hydrophilicity decrease and the loss of antifogging property of all p‐DAME‐co‐HDFD coatings may be due to slight flexibility of hydrophilic segments as with AA chains. [ 31,32 ] To give evidence of the influence of the polymeric chain motion on antifogging properties, p‐AA‐co‐HDFD codeposits ([HDFD] = 20%, t = 10 min) were prepared in such conditions that cross‐linking should take place during plasma deposition.…”

Characterization of functionalized coatings prepared from pulsed plasma polymerization

“…This means determining the influence of different plasma parameters on the appearance of only double C-C, and the retention of acrylic acid and anhydride functions. The pulsed plasma approach offers the possibility of controlling the surface function density by limiting the electron, ion bombardments and the precursor fragmentation [30][31][32][33][34][35][36].…”