Synthesis of silicon carbide nanocrystals and multilayer graphitic carbon by femtosecond laser irradiation of polydimethylsiloxane

Abstract

Laser-based modification of polymer materials has been emerging as a versatile and efficient technique to simultaneously form and pattern electrically conductive materials. Recently, it has been revealed that native polydimethylsiloxane (PDMS) can be modified into electrically conductive structures using femtosecond laser irradiation; however, the details regarding the structures formed by this method have yet to be revealed. In this work, structures were fabricated by focusing and scanning femtosecond laser pulses onto the surface of PDMS. Raman Spectroscopy and Transmission Electron Microscopy (TEM) analyses revealed the formation of silicon carbide (SiC) nanocrystals, as well as multilayer graphitic carbon, in the modified regions of PDMS. The state of the formed material differed depending on the distance from the focal spot, suggesting that photo-thermal effects contributed to the degradation of PDMS into conductive material. Electrical conductivity measurements, in addition to Raman results, indicated that the amount of disorder in the formed graphitic carbon contributes to the electrical conductivity of the fabricated structures.

A Wearable Body Condition Sensor System with Wireless Feedback Alarm Functions

“…It is worth noting that the laser texturing on PDMS at the higher power density can directly promote the formation of graphite (Figure S10, Supporting Information) and silicon carbide to form flexible semiconductor/elastomer composites or for high‐quality PDMS patterning. [ 40–42 ]…”

“…It is worth noting that the laser texturing on PDMS at the higher power density can directly promote the formation of graphite (Figure S10, Supporting Information) and silicon carbide to form flexible semiconductor/elastomer composites or for high-quality PDMS patterning. [40][41][42] More importantly, the sheet resistance (≈44 Ω sq −1 ) of lasertextured LIG/PDMS has a very slight conductivity degradation compared to that of LIG/PDMS (Figure 2d). This is crucial to create LIG-based conductive electrodes for the tilt sensor.…”

Laser Direct Writing of Graphene Quantum Dots inside a Transparent Polymer

“…In addition, typically for the laser-induced graphitization of PI, flake-like products form, whereas in the case of PDMS, particle-like products are typically formed. 46,47 Since PDMS is an organometallic polymer, laser irradiation results in the formation of Si-based products that melt under high temperatures. The formation of a liquid medium can facilitate the formation of nanoparticles, presumably similar to the formation mechanism of nanostructures for laser ablation in liquids.…”

Laser‐Induced Graphenization of PDMS as Flexible Electrode for Microsupercapacitors

“…This groove is possibly due to a more intense production of gaseous products during the writing process as a consequence of the different composition of the starting polymeric substrate with respect to polyimide, and it has been reported in the literature for PDMS substrates treated with 522 nm laser pulses. [ 16 ] This central groove basically divides the LIG path into two distinct parallel lines which exhibit the usual 3D porous morphology, as shown in high‐magnification FESEM images. The thin walls of this characteristic 3D architecture are constituted by few‐layer graphene flakes, as will be shown in the discussion of TEM results.…”

“…This is in accordance with the lower abundance of Si atoms in the starting material due to the presence of 40% TEG. The presence of the nanoparticles is not surprising: laser‐induced synthesis of SiC nanoparticles from PDMS substrates has already been reported in the literature [ 16,18 ] and they are expected to play an important role in the electrical characteristics of the samples, lowering the conductivity of the material. Regarding the graphenized area, for both samples high‐resolution TEM images clearly show the presence of a complex structure of randomly oriented few‐layer graphene domains, characterized by the ≈3.4 Å d ‐spacing of the (002) family of planes in graphite.…”