Fabrication and Characterization of Porous Poly(dimethylsiloxane) (PDMS) Adhesives

Abstract

In this study, we propose a simple low-cost emulsion-based method to fabricate porous poly­(dimethylsiloxane) (PDMS) adhesive films, with a focus on their possible application as wound dressings. In this method, water is added to PDMS to form an emulsion. On film-casting the emulsion and curing it at 120 °C, evaporation of water droplets and PDMS cross-linking result in randomly distributed pores/voids in the bulk of the PDMS film. A huge advantage of the proposed method over conventional approaches is its simplicity owing to the use of water as a porogen. Two variants of the fabrication approach were considered: direct film-casting of emulsion and film-casting of the solvent-mediated emulsion with additional degassing. Films prepared using the first approach demonstrated that the bulk porosity induces significant roughness at their surface. Such films do not make good contact with the substrate, resulting in poor adhesion. Coating the films with a thin viscoelastic layer of PDMS, while retaining the bulk structure, improves the contact of the film with the substrate. These bi-layer films demonstrated remarkable enhancement in adhesion. The second approach involves adding ethyl acetate as a solvent and degassing the emulsion before film-casting, which results in a more controlled porosity and lower roughness at the surface. Compared to the porous films synthesized using the former protocol, these films have a relatively improved contact with the cover plate, resulting in enhanced adhesion. Lastly, through falling weight impact measurements, it was shown that the porous films, in comparison to their nonporous counterpart, were more effective in absorbing the accidental impact shock, which makes them potentially useful in healthcare applications.

Biomimetic Polymer Adhesives

“…Very recently, Mohania et al used an emulsion based fabrication method, using water as a porogen, to fabricate porous PDMS adhesive films . The authors demonstrated that generation of bulk porosity resulted in increased surface roughness, which hindered in proper contact of the adhesive film with the substrate and hence reduced the adhesion (see Figure a,b).…”

“…(d) Scanning electron micrograph of PDMS foam, (e) close-up image of (left) sugar cube (template) and (right) PDMS foam adhesive cube, and (f) load vs displacement data for the adhesive foam and film-terminated adhesive foam. Parts a–c have been reprinted with permission from ref . Copyright 2021 American Chemical Society.…”

“…142 Very recently, Mohania et al used an emulsion based fabrication method, using water as a porogen, to fabricate porous PDMS adhesive films. 143 The authors demonstrated that generation of bulk porosity resulted in increased surface roughness, which hindered in proper contact of the adhesive film with the substrate and hence reduced the adhesion (see Figure 20a,b). However, coating the surface of these films with a thin viscoelastic layer resulted in a significantly enhanced adhesion due to the crack arrest and crack initiation offered by the bulk pore structures along with the additional viscous dissipation and increased compliance (see Figure 20c).…”

Distribution of the Deposition Rates in an Industrial-Size PECVD Reactor Using HMDSO Precursor

“…Many materials should be coated with a thin protective layer to provide an adequate surface finish and stability in harsh environments [1][2][3][4][5]. A variety of techniques have been proposed, and a few have also been commercialized [6][7][8][9][10]. One technique for depositing compact and hydrophobic films similar to polydimethylsiloxane (PDMS) is plasma polymerization.…”

Polydimethylsiloxane-Based Mechanoluminescent Occlusal Splint with the Visualization of Occlusal Force

“…As an alternative occlusion material, the ML elastomer should also have good mechanics and biological performance, which suggests that the employed flexible matrix for the ML elastomer is of great importance. Polydimethylsiloxane (PDMS) is frequently used as the matrix for ML powders because of its high optical transparency, efficient stress transfer ability, and easy fabrication. , Moreover, PDMS shows excellent biocompatibility and permeability, high-temperature resistance, and natural hydrophobicity. − Therefore, the elastomer composed of ML powders and PDMS matrices is promising to replace the existing occlusal materials to possess better overall performance and visualized occlusal inspection.…”