Superglue monomers belong to a family of cyanoacrylates that are known for their very rapid polymerization upon contact with moist surfaces. Their biodegradation and low toxicity make them attractive as medical and veterinary adhesives. Although the fast-acting polymerization characteristics have been successfully utilized to design nanoscale polymeric particles that can carry drugs or other inorganic nanoparticles, it constitutes a significant drawback if one desires to produce other forms of functional biodegradable acrylics, such as coatings, sheets, or nanocomposites. This is because rapid polymerization in air creates highly porous and brittle structures. Here, we address this drawback by reporting a simple and inexpensive method of fabricating highly transparent (>92%) polyethylcyanoacrylate (PECA) coatings by dispersing the monomer in a fragrance-classified green liquid, cyclopentanone. The resulting transparent coatings were hydrophilic but with slippery wetting characteristics, suitable as efficient fog-harvesting templates. Furthermore, another fragrance liquid, benzyl alcohol, is introduced as a plasticizer and co-solvent to overcome its brittleness while retaining its transparency. The same plasticized monomer solutions, dispersing low concentrations of graphene (<0.5 wt %), were allowed to self-assemble on stainless steel surfaces, forming low-friction and anti-wear dry lubricants by decreasing the steel friction coefficient and wear rate by 6- and 10-fold, respectively.
A pH‐based method to tune the tribological and wetting properties of a coating obtained from water‐dispersed perfluorinated acrylic copolymer is demonstrated. The surface‐exposed fluorinated chains and chemical charges of the sprayed coatings can be controlled simply by tuning the pH of the initial water dispersion. The surface properties of the sprayed polymeric coatings remain unmodified when the pH of the water dispersion is reduced (addition of HCl). On the contrary, from dispersions with increased pH (addition of NaOH) a fluoroacrylic polyelectrolyte polymer is formed and clear variations in wetting and tribological properties of the polymeric coatings are observed. Interestingly, coatings' surface adhesion to vulcanizing rubber can be strongly reduced when the pH of the dispersions is in the range 4.5–6.0, which corresponds to a specific ratio between fluorinated chains and chemical charges. Consequently, such coatings can be proposed as low‐cost and easy‐to‐apply alternatives to aqueous release agents for the rubber tires demolding processes, thus having significant implications for the automotive tire industry.
Fabrication of thermal interface materials (TIMs) from sustainable resources is a very challenging task but at the same time of great importance due to the continuously growing problem of electronic waste management. A variety of TIMs comprising synthetic polymers loaded with metallic wires or ceramic nanofillers are commercially available; however, they are usually frail and difficult to recycle. In this letter, we report a simple fabrication process for sustainable bio-based TIMs using regenerated cellulose and graphene nanoplatelets (GnPs). The process relies on forming conductive inks by dissolving post-consumer cotton fabrics and dispersing GnPs in a common solvent, followed by solution casting/drying. The TIM pads become electrically conductive (30 S/m) at 25 wt. % GnP concentrations. Their cross-plane thermal conductivity (k) was estimated to be 5.50 W/mK using infrared thermal measurements on a chip-stack setup. Additionally, the surface or in-plane 2D thermal conductivity was found to be approximately 800 W/mK. In the case of damage, the TIMs can be recycled by re-dispersing in the solvent.
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