Hydrophilic mechanical buffer layers and stable hydrophilic finishes on polydimethylsiloxane using combined sequential vapor infiltration and atomic/molecular layer deposition

Abstract

Polydimethylsiloxane (PDMS) is an important polymer material widely used for microfluidic device fabrication, microcontact lithography, and surface morphology molding. However, the hydrophobic surface limits its functionality. Low temperature atomic layer deposition (ALD) has recently been used to functionalize a wide range of polymer surfaces. In previous research, the authors were able to produce a uniform hydrophilic alumina film coating on PDMS using trimethyl aluminum/water ALD. However, the surface recovered its hydrophobicity after 24–48 h in ambient air or under inert gas storage, which was ascribed to organic species outdiffusion through the ALD layer. This paper reports a stable hydrophilic ALD surface modification on the PDMS. The PDMS substrate was first sequentially exposed to trimethylaluminum and water vapor, allowing the vapors to infiltrate and react to create a mechanical and diffusion buffer layer in the PDMS surface region. This buffer layer helps to nucleate a cohesive hydrophilic ALD or molecular layer deposition (MLD) coating and also helps prevent organic outdiffusion that typically leads to PDMS hydrophobic recovery. The results provide valuable insight into reliable surface energy and mechanical modification of PDMS using vapor-phase precursor/polymer reactions. In addition, molecular layer deposition of “alucone” coatings was also investigated to modify the PDMS surface. The experiment result showed the vapor infiltration and MLD coatings produce a viable and stable hydrophilic surface on PDMS.

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

“…When metal precursors are combined with alcohols or phenols, the resultant material is often called “metalcone” [ 27 ]. Most of the research has been focused on the aluminum-based alucones [ 12 – 13 15 – 16 38 – 39 81 – 97 ], but also zincones [ 13 , 33 , 38 – 39 46 , 51 – 52 56 , 94 – 95 98 – 103 ], titanicones [ 53 , 55 , 95 , 104 – 105 ], and zircones [ 54 , 87 ] have been studied. The schematic structure of ideally growing TMA+ethane-1,2-diol, DEZ+benzene-1,4-diol and TMA+oxiran-2-ylmethanol hybrid films are shown in Fig.…”

Thermal Stability of Gold Nanoparticles Embedded within Metal Oxide Frameworks Fabricated by Hybrid Modifications onto Sacrificial Textile Templates

“…A number of factors suggest that the H 2 O outgassing has little to no effect in NP encapsulation observed with TMA exposure to PA-6, including no evidence of similar effects observed in the infiltration process on PET and PBT polymers that contain little (< 1%) to no water content. 41 We have also previously reported evidence for PA-6 softening and flow during exposure to TMA, suggesting that the TMA significantly effects the polymer chains. 31 Despite the possible competing infiltration mechanisms presented, a uniform layer was observed through the SVI processing considered in this work.…”

Modifying hydrophilic properties of polyurethane acryl paint substrates by atomic layer deposition and self-assembled monolayers

“…[6][7][8][9] One way to create hydrophilic coatings is by depositing oxide layers on the substrate. [10][11][12][13][14][15][16][17] Since many oxides have hydrophilic surfaces, they represent excellent candidates for hydrophilic coatings. However, most oxide deposition methods require high temperatures and are therefore not suited for polymer substrates.…”