Danish Tahir

Degrable, high‐performance piezoelectric materials are critical for implantable and environmentally friendly devices capable of reliable sensing and energy harvesting while safely degrading after use. However, most degrable piezoelectric materials still suffer from limited electromechanical performance. Here, we report a high‐performance poly(3‐hydroxybutyrate):zinc oxide (P3HB:ZnO) composite piezoelectric nanofiber optimized using an integrated artificial neural network‐genetic algorithm framework. The model identified an optimal ZnO content of 4.3 wt.%, resulting in significantly enhanced piezoelectric performance compared with pristine P3HB. The optimized nanofibers achieved a peak voltage sensitivity of 0.382 mV/kPa at 1 Hz and an effective piezoelectric voltage coefficient of 13.65 mV/m·N, with stable output over 1000 loading cycles and a response delay of 318 ms. Biodegradation studies showed approximately 38% mass loss after 6 weeks, while the nanofibers retained measurable piezoelectric functionality within this timeframe. Furthermore, integration with a multichannel sensing platform enabled a proof‐of‐concept AI‐assisted gait‐recognition demonstration. This work presents a scalable machine‐learning‐driven strategy for designing high‐performance sustainable piezoelectric materials for self‐powered transient bioelectronics.

This study investigates the influence of sodium hydroxide (NaOH) surface treatment on the out-of-plane auxetic behavior and mechanical properties of hemp/polylactic acid (PLA) nonwoven composites. Untreated and alkali-treated hemp fibers (2.5 wt.%, 5 wt.%, and 7.5 wt.% NaOH) were used to fabricate needle-punched nonwovens with 50 wt.% PLA. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR) were employed to analyze surface morphology, thermal stability, and chemical changes, respectively. Alkali treatment effectively removed hemicellulose and lignin, enhanced surface roughness, and improved fiber matrix adhesion. Mechanical testing revealed that 5 wt.% NaOH treatment yielded the highest tensile strength due to optimal interfacial bonding and mechanical interlocking. However, out-of-plane Poisson's ratio measurements indicated a decrease in auxetic magnitude with increasing NaOH concentration, with the maximum negative Poisson's ratio of approximately −6.5 observed for untreated composites and −2.3 for treated ones. The results demonstrate that improved interfacial bonding enhances strength but restricts fiber rotation and reorientation, leading to reduced auxetic behavior. This work establishes a direct correlation between fiber surface modification and auxetic tunability, providing valuable insight into designing sustainable, functionally adaptive composites for structural and protective applications.

This study investigates the influence of polyvinyl alcohol (PVA) treatment on bamboo long fibers to improve their performance in epoxy composites. Bamboo fibers were treated with PVA solutions at 1 %, 3 %, and 5 % and incorporated into epoxy matrices fabricated by hand lay-up. Microscopy revealed that 3 % PVA formed a uniform coating on fiber surfaces, enhancing adhesion with the matrix. Mechanical testing showed that PVA treatment improved tensile strength (from 32 to 39 MPa) and modulus (from 0.9 to 1.8 GPa), while impact resistance slightly decreased due to restricted fiber pull-out. Water absorption was also reduced, with 3 % PVA composites exhibiting the lowest uptake. Overall, PVA treatment is demonstrated as an effective and environmentally friendly modification method that enhances the mechanical strength and durability of bamboo/epoxy composites, making them more suitable for structural applications.

Auxetic composites are unique materials with a negative Poisson’s ratio (NPR), that has been of great interest for various applications. Regardless of their exceptional properties, they require special attention due to their non-biodegradable nature. This work focuses on the use of natural hemp fibers as a reinforcement and biodegradable polylactic acid (PLA) as a matrix for making biodegradable auxetic composites. Hemp nonwovens were prepared by the needle-punching method, followed by adding different content of PLA into the nonwoven to fabricate the composite. The out-of-plane auxetic response of needle-punched hemp/PLA composite was achieved by a heat-compression protocol whereas the in-plane auxetic effect was obtained by creating a re-entrant honeycomb structure. Heat-compressed composites exhibited a prominent auxetic effect upon uniaxial loading resulting in the achievement of an out-of-plane auxetic effect. Composite with 50% PLA showed the highest NPR of—6.5 with a tensile strength of 2.1 MPa. The out-of-plane auxetic effect in the heat-compressed composites is due to the tilting and buckling of vertical fiber columns that tend to reorient themselves back to their vertical position upon the application of uniaxial force. Further increase of PLA content not only decreases the NPR but affects the mechanical properties negatively as the excess amount of PLA creates defects inside the composite. Re-entrant honeycomb composite having a PLA content of 50% showed an in-plane NPR of −0.40. The study provides a new approach for the development of biodegradable composites with out-of-plane and in-plane NPR for various applications of auxetic materials.

Energy‐absorbing auxetic composites show flexibility in usage, yet they remain non‐biodegradable, thus creating environmental challenges. Implementing sustainable auxetic materials constructed from natural fibers and biodegradable polymers remains essential for lowering environmental effects. This research involves the fabrication of eco‐friendly auxetic composite using jute and jute‐viscose nonwovens. Scanning electron microscopy and optical microscopy revealed the out‐of‐plane auxetic effect that heat compression produced at different temperatures and pressure levels. The combination of 150°C and 50 psi pressure resulted in out‐of‐plane Poisson's ratios (PR) of −2.6 and −3.0 for jute and jute‐viscose nonwovens. The incorporation of 40% biodegradable polylactic acid (PLA) into the jute and jute‐viscose nonwovens increased auxeticity to −4.5 and −5.0, respectively. Needle punching density controlled the in‐plane auxetic properties, where jute/PLA composites achieved a PR of −0.45, and jute‐viscose/PLA composites achieved a PR of −0.65. The unprocessed nonwoven materials displayed the highest tensile strength of 0.16 MPa for jute and 0.76 MPa for jute‐viscose, but heat treatment diminished this strength level. PLA reinforcement improved composite strength. This study introduces a durable method for designing auxetic materials that can find uses in energy‐absorbing systems as well as protective equipment.Highlights: Evaluating the in‐plane and out‐of‐plane auxetic behavior in needle‐punched jute and jute‐viscose nonwovens. Studying the effect of various temperatures and pressures on the out‐of‐plane auxetic behavior of nonwovens. Fabricating a sustainable composite by reinforcing PLA and examining auxeticity. Temperature and pressure have significant effects on auxetic behavior. Optimizing PLA content further helps in improving auxetic behavior and strength properties.

Bamboo and its hybrid composites were made using the hand lay-up method to evaluate the change in mechanical and physical properties that occurred through filler addition. Density measurements and tensile test results showed an increment in values when a certain percentage of silicon carbide (SiC) was added. As the SiC percentage grows from 0 to 6 %, the density of the hybrid composite increases from 1.15 to 1.36 gm/cc whereas tensile strength increases from 37 MPa to 42 MPa when 4 wt% SiC is added in 20 wt% of the bamboo composite. The scanning electron microscopy (SEM) analysis of tensile fractured samples further supported the improvement in tensile characteristics. To examine the impact and hardness characteristics, composites were subjected to the Charpy impact test and hardness test. 4 wt% of SiC addition in 20 wt% of the bamboo composite decreased the impact strength from 28.79 to 27.43 (×10⁻³ kJ/m²) and increased the hardness from 44 to 55 Hv. The composites’ water absorption behavior demonstrated that the addition of filler lifts the composite’s resistance to absorbing water, preserving the composites’ dimensional firmness and mechanical qualities.

Nanocellulose is the most abundant material extracted from plants, animals, and bacteria. Nanocellulose is a cellulosic material with nano-scale dimensions and exists in the form of cellulose nanocrystals (CNC), bacterial nanocellulose (BNC), and nano-fibrillated cellulose (NFC). Owing to its high surface area, non-toxic nature, good mechanical properties, low thermal expansion, and high biodegradability, it is obtaining high attraction in the fields of electronics, paper making, packaging, and filtration, as well as the biomedical industry. To obtain the full potential of nanocellulose, it is chemically modified to alter the surface, resulting in improved properties. This review covers the nanocellulose background, their extraction methods, and possible chemical treatments that can enhance the properties of nanocellulose and its composites, as well as their applications in various fields.

Life-changing illnesses and fatalities caused by inefficient personal protective clothing and equipment are increasing day by day. The discrepancy between the test standards, environmental conditions, and infield collision is the reason why personal protection equipment and clothing have not yet decreased the number of injuries in various fields such as military and sports. To further increase the efficiency of personal protection materials, auxetic materials are suggested because of their high energy absorption, good permeability, form-fitting ability, and high indentation resistance. Auxetic materials are nonconventional materials with a negative Poisson's ratio and can shrink under compression and expand when subjected to stretching. In comparison to nonauxetic conventional materials, auxetic materials have improved properties that can be useful for personal protection applications. This review focuses on the importance of auxetic materials for personal protection, focusing on reducing the chances of injury and what possible ideas can further benefit the protection products. The first part of the review discusses the auxetic structures and their protection applications followed by the fabrication of auxetic structures. The review will conclude with limitations, economic prospects, and what possible work can further improve the potential use of auxetic materials in personal protection.