ABSTRACT Polydimethylsiloxane (PDMS) is a widely used elastomer owing to its flexibility, optical clarity, ease of processing, and biocompatibility. However, its application in high‐performance systems is often limited by poor mechanical strength, modest thermal endurance, and high gas permeability. Recent advances in additive‐assisted modification using carbon‐based, inorganic, and hybrid nanofillers have demonstrated significant improvements in rheological, mechanical, thermal, and functional performance. This review critically examines the influence of nanofillers on PDMS, focusing on reinforcement mechanisms, rheological behavior, and multifunctional properties. The mechanisms governing property improvements, such as filler–matrix interactions, interfacial bonding, dispersion quality, and surface functionalization, are analyzed in detail. Comparisons are drawn among carbon‐based materials, inorganic fillers, and hybrid systems to provide a comprehensive understanding of structure–property relationships. Applications in microfluidics, flexible electronics, biomedical systems, and protective coatings are also highlighted. Finally, current challenges related to dispersion, large‐scale processing, and biocompatibility are discussed, together with future opportunities in hybrid reinforcement, sustainable additives, and data‐driven materials design for next‐generation PDMS technologies.

Experimentally, the electrochemical behaviour of rGO-doped CaCO3 nanocomposite was determined. Reduced graphene oxide (rGO) was synthesized using graphite rod from the waste pencil battery. The graphite rod was used for the synthesis of rGO nanoparticles and also aided in the management and recycling of waste materials. However, the nanocomposite was synthesized by adding rGO into the calcium carbonate (CaCO3) matrix through a simple approach technique that is chemical-free, non-hazardous, simple, and rapid. The synthesized nanoparticles and nanocomposite were characterized using FESEM and FTIR. While the 5

This research investigates the influence of functionalized reduced Graphene Oxide ( f ‐rGO) on the thermo‐physical properties of nano Calcium carbonate (CaCO 3 ). The nanocomposite was developed by altering the wt. % of f ‐rGO (3 %, 4 %, and 5 %) as filler into nano CaCO 3 through an in‐house developed portable ball mill that is a novel and environmentally friendly method. Numerous characterizations were employed to determine the effect of f ‐rGO on the morphological, structural, thermal, and optical characteristics of f ‐rGO/CaCO 3 nanocomposite. The nanocomposite doped with 5 % f ‐rGO shows a minimum optical bandgap energy of 1.49 eV. Furthermore, the thermal degradation shifts toward a higher temperature range of 566–702 °C, and the crystallinity was improved by incorporating f ‐rGO into nano CaCO 3 . Nano CaCO 3 has an average crystallite size of 86.08 nm while doping f ‐rGO reduces the crystallite size to 67.99, 54.92, and 49.81 nm, respectively. Thermal conductivity improved by 40.90 %, and thermal diffusivity enhanced to 1.924 mm 2 /s when CaCO 3 was doped with 5 % f ‐rGO.

The directional conduction cooling affects the microstructural and tribological features in laser powder bed fusion (LPBF). In this work, annealing treatment was applied on a LPBF-processed Ti-6Al-4 V (Ti-6-4) alloy to reduce flaws and enhance tribological characteristics. Wet linear reciprocating sliding wear test throughout an immense range of normal loads (5–30 N) was employed in the presence of synthetic physiological media (simulated body fluid) at human biological temperature on lateral surface to investigate their comprehensive wear behavior. The universal tribometer was employed to evaluate wear parameters such as wear rate, volume, depth and coefficient of friction. Morphological and mechanical characteristics were executed and correlated with wear and friction. Wear track width deviations were analyzed using scanning electron microscope (SEM), revealing irregular shape variations. Energy-dispersive spectroscopy (EDS) and worn surface examination supported wear and friction findings. The findings suggest that high-density Ti3Al precipitates were produced, and the partial decomposition of α' into α and β took place throughout the annealing treatments. The worn morphologies and wear processes depended considerably on the microstructural features and applied stresses. The HT700 sample had a smoother wear surface and lower COF over a wide range of loads due to the formation of protective tribo-oxide layer. Heat treatment of Ti-6-4 alloy resulted in significant improvements in hardness, elongation (EL) and yield strength (YS), with values increasing from 400 ± 5 to 451 ± 25 VHN, 4.64 ± 0.9 to 6.35 ± 0.2

The convergence of nanotechnology and biomedical engineering has ushered in a new era of advanced materials tailored for high-performance biomedical applications. Nanocomposites that integrate hydroxyapatite (HAP) with reduced graphene oxide (rGO) have garnered significant attention due to their unique synergistic properties. In this study, the mechanosynthesis of rGO/HAP nanocomposite in powder form has been reported, engineered to exhibit excellent thermal conductivity, biocompatibility, and non-cytotoxic behaviour, qualities that position it as a promising candidate for biosensing platforms and biocoating materials for medical implants. Morphological and structural analysis were conducted using FESEM, HRTEM and XRD, confirming the homogeneous mixing of rGO reinforcement in the HAP matrix. Nanorods of HAP measuring 22.5 nm in length and thin, crumbled, transparent nanosheets of rGO were seen. Furthermore, XRD analysis, corroborated by the Williamson-Hall method, indicated that increasing the weight percentage of rGO in the HAP matrix led to a reduction in crystallite size by approximate to 22 %. FTIR analysis reveals the presence of distinct peaks in the nanocomposite sample, while TGA-DTA indicates that an increase in rGO wt.% leads to a shift in degradation temperature to 700 degrees C, in contrast to nano HAP at 610 degrees C. Doping with 5 wt.% rGO has significantly enhanced thermal conductivity by approximate to 86 % and diffusivity by approximate to 126 %. The MTT assay results demonstrate that HAP nanopowder exhibits enhanced biocompatibility at lower concentrations, up to 50 mu g/mL. In contrast, the rGO/HAP nano-composite shows marginal cytotoxicity, categorizing it as a grade I biomaterial.

Biocompatible, biodegradable polymers like polylactic acid (PLA) are increasingly used in biomedical applications due to their renewable origin and favorable physicochemical properties. PLA stands out as a sustainable alternative in both medical and industrial fields. The present work explores the mechanical attributes of 3-D printed PLA, employing a blend of atomistic, analytic, and experimental techniques. The mechanical properties of PLA fabricated by the fused deposition modeling (FDM) method were evaluated using a universal testing machine (UTM). The atomistic simulations utilize molecular dynamics (MD) to examine the physical and mechanical characteristics of PLA at the atomic level. Additionally, an analytical model was proposed using classical laminate theory to predict the tensile strength. The combined approach of atomistic simulation, analytical, and experimental methods enabled a comprehensive understanding of the mechanical behavior of printed PLA. Based on the observation, the tensile strength was found to be 30.675 MPa, while the analytical and MD models predicted 30.975 and 450 MPa, respectively. The analytically predicted values and experimental data of tensile strength demonstrated a reasonable agreement, thereby validating the model. The findings pave the way for the rational design and optimization of 3-D printed PLA materials for diverse engineering applications, including aerospace, biomedical devices, and consumer products.

The use of post heat treatment is essential in order to enhance the microstructure of additively produced Ti-6Al-4 V to meet the specific requirements set out by the aerospace and automotive sector. Nevertheless, the comprehensive understanding of the correlation between the distinctive microstructural characteristics resulting from heat treatment and the associated mechanical characteristics of Ti-6Al-4 V (Grade 23) produced using laser powder bed fusion (LPBF) technique remains insufficient. The present research work systematically examines the impact of annealing heat treatments (HT) on the microstructural changes and resulting mechanical characteristics of top, side and basal surface of Ti-6Al-4 V (Grade 23) alloy processed through LPBF method. The microstructure was characterized using optical microscopy (OM) and scanning electron microscopy (SEM). The observed microstructure of the as-deposited sample characterized by a coarse lamellar, needle-like and complicated basketweave structures consisting of α + α′ phases. The complex-shaped needle-like α + α′ structures, rod and particle-shaped structure with β phase was observed in HT sample. Elemental analysis of microstructure was performed using energy-dispersive x-ray spectroscopy (EDS). In addition to inducing phase change, heat treatment also effectively minimizes internal defects such as pores, internal cracks and delamination. The tensile strength and microhardness were further examined, according to the various microstructures. The as-built samples had a high tensile strength (UTS) of 1246 ± 10 MPa, but they displayed low ductility with limited elongation of 4.64 ± 0.9

Annealing treatments was implemented on a laser powder bed fusion-processed (LPBF) Ti-6Al-4V (Ti Gr23) alloy to improve its tribological attributes. Wet reciprocating wear tests at 5 N normal load and sliding velocities (5 mm/sec) were utilised to evaluate their wear behavior. The test was performed using a SS304 spherical ball of diameter 5 mm and a stroke length of 5 mm in simulated body fluid (SBF) at body temperature. A set of optimal process parameters were used for the fabrication of porous less Ti64 sample using porosity parametric simulation in Additive ANSYS software. The microstructural and mechanical characterization were performed and corelated wear mechanism. The results indicate that the partial decomposition of alpha'->alpha + beta occurred during the annealing treatments. A needle-like martensite alpha' phase was noticed on the as-sintered sample. The worn morphologies and mechanisms depend significantly on the microstructural characteristics while microstructural characteristics depend significantly on annealing treatment. Scratches observed along the wear track of Ti64 alloy, accompanied by islands of microscopically smooth oxide layers detaching from the surface, suggest a mixed mode of wear characterized by both abrasive and adhesive mechanisms. Annealing treatment was improved the tribological behaviour of Ti64 alloy.

This study involves the synthesis of reduced graphene oxide (rGO) using carbon rods derived from used pencil batteries. A nanocomposite of rGO-CaCO3 was synthesized using a simple approach using an in-house developed ball mill, with 5% (wt. %) of rGO in CaCO3. Previous investigations restricted the integration of the rGO/CaCO3 nanocomposite to lesser amounts (1%-5%). The aim of this research is to experimentally analyze the effect of higher inclusion of the nanocomposite on the structural, optical, and mechanical properties of PDMS. An enhanced elastomer was subsequently developed, fortified with the synthesized nanocomposite at varying percentages (5%-40% wt.%). The effect of the nanocomposite was assessed using various characterization techniques, including FESEM, XRD, UV-Vis, XPS, and RAMAN. The incorporation of the nanocomposite markedly enhanced the structural and mechanical characteristics of PDMS. As the nanocomposite wt.% content increased, the optical band gap decreased. With a value of 1.27 eV, the 40% elastomer demonstrates the lowest optical band gap energy. The maximum failure force for unmodified PDMS was recorded at 12.93 +/- 0.388 MPa, while the incorporation of 40% rGO/CaCO3 nanocomposite increased this value to 27.95 +/- 0.838 MPa. The tensile stress rose to 0.93 +/- 0.046 following the addition of the 40% nanocomposite. Such superior properties make the elastomer applicable in flexible electronics, biomedical implants, sensors, protective coatings, and transparent structural materials.

The nonlinear periodic response of viscoelastic laminated composite plates subjected to harmonic excitation is carried out in time domain using the generalized Maxwell model in the form of a Boltzmann integral. The integral form of the viscoelastic constitutive relation is converted to the incremental form for the finite element formulation based on the Reissner–Mindlin plate theory incorporating von Karman geometric nonlinearity. The recursive relations are developed to compute the current time-step solution using only the previous time-step solution. The periodic response is obtained using shooting technique coupled with Newmark’s time integration and arc length continuation method. The implementation of the shooting technique for the Boltzmann Integral based viscoelasticity done for the first time in this study involves derivation of a number of additional recursive relations and initial conditions at the beginning of each shooting cycle. The nonlinear periodic vibration characteristics such as frequency response, damping factor, steady-state response history, phase plane plots, and frequency spectra are presented for viscoelastic plates with different boundary conditions and lamination schemes. Further, the influence of relaxation time and number of Maxwell elements on the frequency response characteristics are investigated. It is seen that the shooting technique is capable of predicting periodic responses of viscoelastic dynamical systems directly from the second-order equations of motion and is more efficient than the direct time integration method. The nonlinear response of viscoelastic plates predicted using the equivalent elastic model with Rayleigh proportional damping (having same linear frequency response) is found to be significantly different from the one predicted using viscoelastic constitutive model.

Additive manufacturing (AM) becomes the interest of many manufacturers because of their advantages in terms of fabrication of complex geometry parts. Fused deposition modeling (FDM) is gaining popularity as a solid-based AM technique for polymer materials due to its cost-effectiveness, minimal material waste, and ability to construct intricate components with ease. Mechanical and fractural behavior of fabricated parts depends upon the process parameters. In this research work mechanical behavior in terms of tensile strength and fracture analysis has been investigated. The FDM technique was utilized to manufacture a tensile specimen utilizing polylactic acid (PLA) material. The additive manufacturing process involves the construction of parts through the sequential deposition of material, layer by layer. Certain constructed components exhibit anisotropic characteristics. The utilization of a scanning electron microscope (SEM) has been employed to analyze the surface morphology of fractures in relation to the variables involved in 3D printing. The uniaxial tensile test simulates using linear finite element analysis (FEA) and a model is developed to verify the stress/strain response. The finding shows that the created numerical model might be utilized in linear FEA analysis of 3D-printed PLA specimen expected to endure tensile stress.

The quality of the fabricated part in the Fused Deposition Modeling (FDM) technique is primarily influenced by the printing variables. Therefore, it is crucial to select the parameters appropriately in order to enhance the qualities of the build specimen. In light of this, this research investigated experimentally and statistically the influence of several printing parameters, like layer thickness, printing speed, and the density of infill, on mechanical properties using polylactic acid (PLA) material. On the basis of Taguchi's factorial design model, nine trials established. The PLA parts manufactured on the FDM printer and mechanical properties evaluated using uniaxial tensile and hardness test. The Signal-to-Noise ratio (S/N) was being used to identify the best combination of the printing parameters. Analysis of Variance (ANOVA) used to find the significant variables and how they affected mechanical properties. In addition, a linear regression analysis performed to estimate the tensile strength ( sigma t ) and hardness of the manufactured component. The scanning electron microscope (SEM) was utilised for fractural surface analysis. The results reveal that only one factor, infill density (100 %), is statistically significant and have a substantial effect on the tensile strength (88.98%). Printing speed have more effect (55.38%) and layer thickness have the least affect (18.66%) on the hardness. Last, but not least, the confirmation test demonstrates that the experimental and statistical findings are consistent.

The linear forced vibration characteristics of viscoelastic variable stiffness laminated composite plates (VVSLC) are studied using a generalized Maxwell model and finite element method. The integral form of the viscoelastic constitutive relation is converted to the incremental form for finite element formulation based on the Reissner-Mindlin plate theory. The recursive relations are developed to compute the current time-step solution using only the previous time-step solution. The periodic response directly in the time domain is obtained using shooting technique coupled with Newmark's time integration method. The implementation of shooting technique for Boltzmann integral-based viscoelasticity for curvilinear fibre composite plates is done for the first time in this study. For the comparison purpose, the response/resonance frequency/modal loss factor is also obtained using equivalent complex modulus based viscoelastic correspondence principle. It is observed that the variation in fibre orientation and boundary conditions leads to significant variations in response, stress/moment resultant amplitude and the damping factor of the VVSLC plates. Further, the present time domain based approach is capable of predicting damping factor at all forcing frequencies whereas complex eigenvalue analysis can predict damping factor only at discrete resonance frequency. Based on the detailed studies, it is found that the curvilinear fibre composite plates depict a significant reduction in response/moment resultants compared to straight fibre composite plates.

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The tribological behaviour of the Ti-6Al-4 V biocompatible alloy fabricated using laser powder bed fusion (LPBF) was experimentally investigated for prosthesis implants. Annealing heat treatment was executed to improve its tribological performance. The microstructure and microhardness characterization were performed using scanning electron microscope (SEM) and Vickers microhardness. The wear test was processed using a SS304 spherical ball in simulated body fluid (SBF) at body temperature. The ball on a flat tribometer was used to determine wear rate, depth, width, and friction coefficient at 15 N. The results revealed that a needle-like martensite alpha' structure was noticed on the as-deposited sample. Microstructural characterization significantly affects wear morphologies. The heat-treated specimen showed a more desirable wear performance than the as fabricated.

Increasing the thermal stability and thermal conductivity of polydimethylsiloxane (PDMS) is a crucial issue for thermal applications. This paper focuses on enhancing PDMS's thermal and structural properties by incorporating nanocomposite into the PDMS matrix. An investigation of the impact of rGO-CaCO3 nanocomposite on the thermal and structural properties of PDMS was performed using Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), the thermogravimetric analysis and differential thermal analysis (TGA-DTA), and thermal analyzer tests. It was observed that PDMS doped with rGO-CaCO3 nanocomposite shows better thermal stability, thermal conductivity, and higher crystallinity. The thermal stability was enhanced significantly by adding a 5% rGO-CaCO3 nanocomposite, and the initial and end degradation temperatures rose to 492 degrees C and 605 degrees C, respectively. The thermal conductivity of pure PDMS is approximately 0.17 W/mK, whereas a conductive elastomer filled with 5% rGO-CaCO3 nanocomposite exhibits a thermal conductivity of 0.44 W/mK at a temperature of 20 degrees C. In contrast, the thermal diffusivity is enhanced from 0.13 mm(2)/s to 0.366 mm(2)/s. Additionally, the Fourier Transform Infra-Red (FTIR) spectrum at 1411 cm(-1) becomes sharp and noisy, and an additional peak arises at 1398 cm(-1), corresponding to the vibrational rocking of the C=C bond and C-O-C bond in CaCO3 and rGO.

Additive manufacturing is regarded as a very efficient fabrication technique since it permits the manufacturing of any three-dimensional product. The present work determines the effect of various infill pattern on the mechanical properties in term of tensile strength, yield strength and hardness of poly-lactic acid (PLA) samples fabricated by fused deposition modeling method. The mechanical behaviour of the 3D-printed PLAs investigated using dog-bone specimens with six distinct infill patterns: line, triangle, tri-hexagon, cubic, octet, and gyroid. The mechanical characteristics were evaluated using the uniaxial tensile test and shore D type hardness tester. The strain and deformation criteria were employed to substantiate the ductile and brittle characteristics. The fractural surface morphology analyzed using the field emission scanning electron microscope. Nonlinear Finite Element Analysis (FEA) was employed to simulate the uniaxial tensile test and establish a Yeoh third order hyperelastic material model for the predictions of the stress-strain response. This model is chosen for its precise ability to predict the nonlinear stress-strain responses for significant deformation and is crucial in applications that involve high degrees of flexibility and elasticity, such as in tire modeling, polymer and elastomer analysis, sports equipment designing, 3D printed components etc. Results revealed that the cubic infill had a maximum tensile strength 32.648 ± 1.42 MPa and octet infill had a minimum tensile strength 22.373 ± 0.79 MPa. The majority of experimental data indicated a brittle behaviour for line-infilled, but triangular, trihexagonal, cubic, octet, and gyroid infill patterns demonstrated ductile behaviour. In comparison to other geometrical infills, cubic shown relatively superior mechanical responses. Consequently, the geometrical infill effect plays a significant role in finding the appropriate mechanical property for industrial applications. The developed material model possesses potential utility in non-linear FEA investigations pertaining to 3D printed PLA objects that are predicted to sustain tensile strength.

Current highly integrated devices require heat interface materials with excellent heat conductivity. A simple approach was employed to synthesize thermally conductive and outstanding thermal stability nanocomposite. Calcium carbonate nanoparticles (nano CaCO3) reinforced with reduced graphene oxide (rGO) nanoparticles (rGO/CaCO3) are synthesized using a novel process, and the effect of rGO in CaCO3 structure is examined by Field Emission Scanning Electron Microscope, X-ray diffraction, TGA-DTA, and thermal conductivity. The experimental results show that adding rGO resulted in higher crystallinity and thermal stability. As the wt.% of rGO increases from 1 to 5%, the crystallite size was suppressed by 21.06%, 27.39%, 32.48%, 41.5%, and 45.30%, respectively, compared to the pure nano-CaCO3. Additionally, rGO enhances the thermal conductivity by 35.31% and thermal diffusivity to 1.834 mm2/s by adding 5% rGO.