Rapid mold-free fabrication of long functional PDMS fibers

Abstract

Polydimethylsiloxane (PDMS), an optically transparent and inert material, is widely used in biological and semiconductor applications owing to its excellent chemical stability and moldability. This study proposes a thermally induced wet spinning method for the fabrication of long PDMS fibers with a constant width. PDMS is a thermoset polymer that undergoes chemical crosslinking when heated, and the thermally induced wet spinning process allows for the formation of fibers without a mold. A rapid thermal curing step was used to instantly solidify the thermoset polymer, where immediate chemical crosslinking of fluid PDMS solution was achieved upon contact with an oil coagulation bath at 180–230 °C. A rapid stretching process was applied to pull out and control the width of the fiber, and the PDMS was stretched at a rate of 1.2–12.5 m/min during the crosslinking process. The fabricated pristine PDMS fibers were transparent and maintained a crosslinked network with excellent mechanical strength. In addition, the PDMS fibers were functionalized with silica nanoparticles, carbon nanotubes, and pores to adjust their transparency/opacity, conductivity, and heat insulation properties, respectively, for various applications. The proposed thermally induced wet spinning method shows promise for overcoming the limitations of existing molding methods, in which the PDMS fibers cannot be lengthened. Furthermore, the process is environmentally friendly and economical owing to the use of edible canola oil, which reduces the volume of harmful solvents and additives during fiber production.

Functional PDMS Elastomers: Bulk Composites, Surface Engineering, and Precision Fabrication

“…This solves the problems associated with the generation of solvent vapors when using conventional wet spinning. [ 338 ] Electrospinning enables the preparation of PDMS fibers at relatively low temperatures. PMMA can be added to the PDMS precursor to enhance the chain entanglement for better electrospinning.…”

“…This solves the problems associated with the generation of solvent vapors when using conventional wet spinning. [338] Electrospinning enables the preparation of PDMS vinyl-functionalized PDMSs gelated under UV illumination and then thermally cured. Reproduced with permission.…”

Programmable and Weldable Superelastic EGaIn/TPU Composite Fiber by Wet Spinning for Flexible Electronics

“…The conductivities of the fibers were achieved using different approaches, including blending conductive materials, such as graphene, 37 carbon nanotubes, 38,39 silver nanowires, 32,40 and MXene, 41,42 with elastomers to create composite fibers. 27,43,44 Alternatively, conductive materials can be injected into the core of the elastic fibers 45 or modified to form a conductive layer on the surface of elastic fibers. 46,47 Liu et al developed highly ductile sheath-core conductive fibers by wrapping carbon nanotube sheets around stretched rubber fiber cores along the direction of the fiber.…”

“…Among these, elastomeric polymers such as polydimethylsiloxane (PDMS), − Ecoflex, , styrene-butadiene-styrene (SBS), − and thermoplastic polyurethane (TPU) , are often preferred because of their elasticity and stretchability, which are essential characteristics of fibers. The conductivities of the fibers were achieved using different approaches, including blending conductive materials, such as graphene, carbon nanotubes, , silver nanowires, , and MXene, , with elastomers to create composite fibers. ,, Alternatively, conductive materials can be injected into the core of the elastic fibers or modified to form a conductive layer on the surface of elastic fibers. , Liu et al developed highly ductile sheath-core conductive fibers by wrapping carbon nanotube sheets around stretched rubber fiber cores along the direction of the fiber . In another study, Zhao et al fabricated a stretchable fiber-based triboelectric nanogenerator (F-TENG) as a wearable biosensor by sequentially covering Ecoflex fibers with multiwalled carbon nanotubes (MWCNTs) and polyaniline (PANI) and then winding the varnished wires …”

Super-hydrophobic and resilient hybrid silica aerogels for thermal insulation, energy harvesting, and electrical applications in harsh environments

“…Moreover, it is relatively simple to modify PMHS's structure and tailor its properties, such as enhancing its hydrophobicity. [28][29][30] The flexibility and ease of shaping aerogels based on PMHS make them particularly valuable for applications requiring conformable materials. Lin et al introduced a novel composite by employing PMHS and TEOS as precursors through a straightforward sol-gel process.…”