Structure–property correlation of silicone hydrogels based on 3‐[tris(trimethylsilyloxy)silyl]propyl methacrylate monomer

Elastomeric Ionic Hydrogel-Based Flexible Moisture-Electric Generator for Next-Generation Wearable Electronics

Rapid consumption of traditional energy resources creates utmost research interest in developing self-sufficient electrical devices to progress next-generation electronics to a level up. To address the global energy crisis, moisture-electric generators (MEGs) are proving to be an emerging technology in this field, capable of powering wearable electronics by harvesting energy from abundantly available ambient moisture without any requirement for external/additional energy. Recent advances in MEGs generally utilize an inorganic, metal, or petroleum-based polymeric material as an active material, which may produce sufficient current but lacks the flexibility and stretchability required for wearable electronics. Herein, we prepared an elastomer-based ionic hydrogel as an active material, and an MEG was fabricated by placing the ionic hydrogel on a PET sheet with two copper tapes on both sides of the hydrogel. The preparation of the hydrogel was thoroughly optimized and characterized in terms of spectroscopic analysis, swelling, water retention, and mechanical and rheological studies. The highly stretchable (350%) fabricated MEG is capable of producing a short-circuit current (JSC) of 16.1 μA/cm2, an open-circuit voltage (VOC) of 0.24 V, and a power density of 3.86 μW/cm2. The synergistic effect of the ion concentration gradient and the redox reaction on electrodes can be considered MEG's working principle. Apart from the current generation, this device is also used as a self-powered electronic sensor to monitor different physical activities by measuring breathing patterns. This prepared device is also capable of sensing the proximity of a hand. Therefore, our low-cost, easily fabricable, sustainable MEG device can be a potential aspirant for next-generation self-powered wearable electronics in healthcare applications.

Controlled Methodology for Development of a Polydimethylsiloxane-Polytetrafluoroethylene-Based Composite for Enhanced Chemical Resistance: A Structure-Property Relationship Study

Polydimethylsiloxane (PDMS) polymers are highly appreciated materials that are broadly applied in several industries, from baby bottle nipples to rockets. Momentive researchers are continuously working to understand and expand the scope of PDMS-based materials. Fluorofunctional PDMS has helped the world to apply in specialty applications. Efforts are taken to develop such siloxane-fluoropolymer composite materials with good thermal, solvent, and chemical resistance performances. We leveraged inherently flexible PDMS as the model matrix, whereas polytetrafluoroethylene (PTFE) was used as the additive to impart the functional benefits, offering great value in comparison to the individual polymers. The composites were made at three different mixing temperatures, that is, 0-35 °C, and different loadings of PTFE, that is, 0.5-8% (w/w), were selected as the model condition. A strong dependency of the mixing temperature against the performance attributes of the developed composites was noted. Mechanical and thermal stability of the composites were evaluated along with optical properties. X-ray diffraction demonstrated the change in the crystallite size of the PTFE particles as a function of processing temperature. Compared to the phase II crystallite structure of the PTFE, the fibrils formed in phase IV imparted a better reinforcing capability toward the PDMS matrix. A synergistic balance between higher filler loading and mechanical properties of the composite can be achieved by doping the formulation with short-chain curable PDMS, with 238% increment of tensile strength at 8 wt % PTFE loading when compared to the control sample. The learning was extended to check the applicability of doping such PTFE powder in commercial liquid silicone rubber (LSR). In the window of study, the formulated LSR demonstrated improved mechanical properties with additional functional benefits like resistance toward engine oil and other chemical solvents.