Polydimethylsiloxane Composites Research Articles

Bio-inspired smart composite architecture for thermally tunable green EMI shielding

Bio-imitating externally stimulated smart flexible composites are highly sought after for the innovations of next-generation advanced artificial intelligence-based electronic technologies, such as robots, defense, wireless and satellite communications, etc., to protect from electromagnetic interference (EMI). Herein, eco-friendly active guest in passive host composite of polydimethylsiloxane (PDMS)/silver-doped zinc stannate (SZTO)/single wall carbon nanotubes (SWCNT) containing an active fluid (water) was fabricated for thermally tuned smart EMI shielding. This soft robust composite with ultra-low fillers integrates temperature induced outstanding smart EMI shielding capabilities in the 14.5 GHz to 20 GHz frequency band. The water serves as a temperature responsive active phase, enhancing the radiation-shielding performance up to 50.4 dB at 100 °C. Additionally, the composite exhibits a green index greater than six, indicating an extraordinary absorption-dominated green shielding response. Hence, this design strategy enables the development of externally stimulated multifunctional autonomous composite architecture for smart green EMI shielding.

Harnessing highly efficient triboelectric sensors and machine learning for self-powered intelligent security applications

In the contemporary epoch, distinguished by a transition from the internet-of-things (IoT) to the artificial intelligence of things (AIoT), individual electronic appliances necessitate inherent power-generation, independence from internet connectivity, and an imbued degree of intellect. Devices governed by pressure or strain sensors particularly demand such attributes. Responding to this technological imperative, our study endeavored to conceive an intelligent door security apparatus grounded on the universally adopted numerical input system. Despite the commercialization of identification systems such as fingerprint, iris, or facial recognition, these mechanisms suffer from susceptibility to a variety of functional aberrations. Consequently, our investigation concentrated on a security system predicated on numerical input. This necessitated the formulation of a swift, self-powered pressure sensor characterized by sensitivity to minute pressure changes. As such, we engineered a triboelectric pressure sensor incorporating a composite of Ti3C2-based MXene and polydimethylsiloxane (PDMS) as the electronegative stratum, and Nylon functioning as the electropositive layer. Addressing the sensor's intrinsic deficiency in sensitivity to pressure, we augmented the MXene-PDMS composite's surface with an out-of-plane wavy structure, and utilized a Nylon stratum composed of nanofibers, thereby amplifying the contact area under pressurized conditions. This meticulously developed sensor displayed a sensitivity metric of 0.604 kPa−1 at 15 kPa, and notably, the swiftest response times recorded amongst triboelectric pressure sensors to date. Post attachment of the sensor to a numeric keypad (ranging from 0 to 9), we meticulously measured the signal alterations contingent on each key press, resulting in a comprehensive dataset. Employing a multitude of machine learning algorithms, we realized an exemplary degree of precision in both training and testing phases. The pragmatic implications of this work are noteworthy. Not only does our technology facilitate the unlocking of a door by entering the correct numerical code, but it is capable of recognizing distinct triboelectric signal patterns, corresponding to the specific manner of key entry by an authorized user, offering an additional dimension of security.

Machine-learned constitutive relations for mechanoluminescent ZnS:Cu–PDMS composites

Materials with novel properties, such as emerging smart materials, offer a design challenge to researchers who want to make use of their unique behaviors. The complex nature of these material responses can be difficult to model from a physics-based understanding as a full description of the multi-physics, multi-scale, and non-linear phenomena requires expertise from various scientific disciplines. Some new smart materials, such as the mechanoluminescent (ML) copper-doped zinc sulfide (ZnS:Cu)-embedded in polydimethylsiloxane (PDMS) (ZnS:Cu–PDMS), lack a constitutive model or an agreement on the mechanisms of action behind the unique material properties. As constitutive equations are essential to engineer devices, with existing knowledge gap in underlying physics of smart materials, a viable approach is to use empirical data for deriving constitutive equations. However, it is challenging to derive constitutive equations on non-linear, multi-variate, and multi-physics relationship using conventional data processing approaches due to the size and complexity of the empirical data. In this work, a machine learning framework is proposed for ones to derive constitutive equations using empirical data for novel materials. The framework is validated by creating constitutive models for ZnS:Cu–PDMS elastomeric composites undergoing a variety of tensile load patterns. To avoid confinement of the models to the programming environment, in which they are developed, numerical fits of the machine-learned models are created as constitutive equations for the non-linear, multi-variate, and multi-physics ML properties. These models can be used when designing ML ZnS:Cu–PDMS to develop devices to harness the unique ML properties.

A soft tactile sensing array with high sensitivity based on MWCNTs-PDMS composite of hierarchically porous structure

The advancement of wearable tactile sensors that involves with high sensitivity under ultra-low pressures is crucial for varieties of human-machine interactive applications, like smart phones, healthcare monitoring, and electronic skins. Here in this paper, a soft capacitive tactile sensing array is introduced based on hierarchically porous multi-walled carbon nanotubes (MWCNTs)-polydimethylsiloxane composite, which leads to sensitivity improvement attributing to a synergistic effect of the hierarchically porous elastomer and conductive MWCNTs supplements. The proposed device exhibits superior pressure-sensing performances, with high sensitivity (3.58 kPa−1) under small mechanical stimuli (<80 Pa), broad measuring range (0–265 kPa), fast response time (<45 ms), good repeatability, minimum limit of detection (<10 Pa), as well as low-hysteresis, allowing efficient sensing of pressure from all types of sources, from vulnerable signals such as human breathing, artery and venous pulses, and soft human finger touch to possible brutal variations such as sudden change of object weight or prompt collide. Moreover, extensive body attached experiments confirm that the soft tactile sensing array is fully human compatible and capable for a variety of human-machine interfaces and health monitoring applications.

Boosting Thermoelectric Power Factor of Carbon Nanotube Networks with Excluded Volume by Co-Embedded Microparticles.

Carbon nanotube (CNT) networks embedded in a polymer matrix have been extensively studied as a flexible thermoelectric transport medium over the recent years. However, their power factor has been largely limited by the relatively inefficient tunneling transport at junctions between CNTs and the low-density conducting channels throughout the networks. This work demonstrates that significant power factor enhancements can be achieved by adding electrically insulating microscale particles in three-dimensional CNT networks embedded in the polymer matrix. When silica particles of a few μm diameters were co-embedded in single-walled CNT (SWCNT)-polydimethylsiloxane (PDMS) composites, both the electrical conductivity and the Seebeck coefficient were simultaneously enhanced, thereby boosting the power factor by more than a factor of six. We found that the silica microparticles excluded a large volume of the composite from the access of CNTs and caused CNT networks to form around them with the polymer as a binder, resulting in improved network connectivity and alignment of CNTs. Our theoretical calculations based on junction tunneling transport for three-dimensional CNT networks show that the significant power factor enhancement can be attributed to the enhanced tunneling with reduced junction distance between CNTs. Additional power factor enhancement by a factor of three was achieved by sample compression, which further reduced the mean junction distance to enhance tunneling but also reduced the geometric factor at the same time, limiting the enhancement of electrical conductivity.

Effect of Photoinitiators Doped in PDMS for Femtosecond-Laser Writing: Characterization and Outcomes.

Herein, we have characterized in depth the effect of femtosecond (fs)-laser writing on various polydimethylsiloxane (PDMS)-based composites. The study combines systematic and nanoscale characterizations for the PDMS blends that include various photoinitiators (organic and inorganic agents) before and after fs-laser writing. The results exhibit that the photoinitiators can dictate the mechanical properties of the PDMS, in which Young's modulus of PDMS composites has higher elasticity. The study illustrates a major improvement in refractive index change by 15 times higher in the case of PDMS/BP-Ge [benzophenone (BP) allytriethylgermane] and Irgacure 184. Additional enhancement was achieved in the optical performance levels of the PDMS composites (the PDMS composites of Irgacure 184/500, BP-Ge, and Ge-ATEG have a relative difference of less than 5% in comparison with pristine PDMS), which are on par with glasses. This insightful study can guide future investigators in choosing photoinitiators for particular applications in photonics and polymer chemistry.

Broadband Electromagnetic Properties of Engineered Flexible Absorber Materials

AbstractFlexible and stretchable materials have attracted significant interest in wearable electronics and bioengineering fields. Recent developments also incorporate embedded microwave circuits and systems with engineered flexible materials that operate over a broad frequency range (≈1–100 GHz). Herein, a simple flip‐chip technique is used to evaluate frequency‐dependent electromagnetic properties of flexible materials and applied to evaluate engineered microwave absorbers based on self‐biased barium hexaferrite composites. On‐wafer error correction and de‐embedding techniques are applied to determine broadband electromagnetic properties of the material‐loaded transmission lines by placing the materials on top of coplanar waveguide transmission lines. Finite‐element simulations along with broadband measurements were employed to estimate the electromagnetic material properties. To demonstrate, flexible polydimethylsiloxane (PDMS) composites are fabricated with barium hexaferrite nanoparticles and complex permittivity and permeability of the composites are quantified under zero magnetic field bias up to 110 GHz. Frequency‐dependent composite permeability is fitted to models describing the ferromagnetic resonance of the self‐biased barium hexaferrite nanoparticles in polydimethylsiloxane, and constituent nanoparticle properties are estimated using the Maxwell–Garnett mixing model. This study paves the way to exploit a wide range of engineered materials in flexible, wearable, and biomedical electronics applications and presents a convenient methodology to extract important broadband electromagnetic properties of nanoparticles for customized electromagnetic applications.

Optimization of electrical and mechanical properties of a single-walled carbon nanotube composite using a three-roll milling method

In this study, the electrical and mechanical properties of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composites were optimized using a three-roll milling dispersion method. Depending on the number of CNT walls, such as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), the three-roll milling conditions required to optimize the electrical conductivity of CNT/PDMS composites are quite different. In addition, the mechanical properties of the CNT/PDMS composites depend on the dispersion time. These properties were improved under an appropriate three-roll milling time but gradually deteriorated after excessive processing time. To demonstrate and optimize this phenomenon, various mechanical, electrical, and thermal properties of the CNT/PDMS composites were measured with respect to the type of CNT, milling time, and filler weight fraction. Morphological and structural analyses were also conducted on the CNT fillers and composites after milling.

Impact of WO3 and BaO nanoparticles on the radiation shielding characteristics of polydimethylsiloxane composites

Abstract In this study, we developed flexible composites using silicone rubber (SR) or polydimethylsiloxane as the matrix and WO3 and BaO nanoparticles as filler to analyze their radiation-shielding performance. The linear attenuation coefficient (LAC) values for the prepared composites were reported to range from 0.059 to 1.333 MeV by using the experimental method. At 0.059 MeV, the SR with 40% of BaO NPs possesses the highest LAC, followed by SR with 20% of BaO and WO3 NPs. The SRs S-2 and S-4 that contain WO3 and/or BaO exhibit continuously greater LAC values than the sample S-1. Numerically, the LAC for S-2 (with 40% of BaO NPs) is 1.6 times greater than that for S-1 (free BaO and WO3) at 0.662 MeV, while the LAC for S-2 is 1.47 times more than that for S-1 at 1.275 MeV. We examined the impact of the thickness of the prepared composites on the attenuation performance by studying the transmission factor (TF) at two different thicknesses (1 and 2 cm). For S-1 and S-2, the TF decreases due to the increase of the thickness from 1 to 2 cm. The TF for S-1 with a thickness of 1 cm is 75% at 0.059 MeV, while it is 56% (for 2 cm). We evaluated the percentage decrease in the TF at 0.059 MeV for every SR as the thickness changes from 1 to 2 cm. For S-3, S-4, S-5, and S-6, the percentage decrease in the TF is extremely significant varying from 98% to 99%. This suggests that increasing the thickness of these SR samples from 1 to 2 cm has a major effect on the shielding capabilities they possess, particularly at low energies.

Spiderweb-inspired fabrication of 3D MXene hybrid filler with multilayer and multiscale features for multifunctional polydimethylsiloxane composites

Polymer-based composite with high thermal conductivity and excellent fire safety is urgently desired and required in the field of thermal management of advanced electronic devices. In this study, inspired by the structure of a spiderweb, we reported a polymer composite with three-dimensional (3D) interconnected spiderweb-like structures by assembling adsorption of transition metal carbides/nitrides (MXene) and diethylenetriaminepenta(methylene-phosphonic acid) coordinated cobalt ions complex. In this composite, MXene combined with the coordination complex forms a 3D network structure with multi-layer/-scale features, which enables high cross-plane thermal conductivity (∼0.59 K w-1m−1) and excellent flame retardancy, especially including effective inhibition of toxic CO and asphyxiating CO2 production. Notably, the 3D MXene networks embedded in the polymer matrix impart the composite with an intelligent damage detection function that is able to detect the depth of cracks. This bioinspired strategy provides a promising approach to creating high-performance polymer-based composites.

Insights into the acoustic field-assisted inkjet printing of graphene-reinforced polydimethylsiloxane composites

The silicon-based organic polymer polydimethylsiloxane (PDMS) has been widely used in biomedical, optical, and mechanical industries due to its outstanding biocompatibility, and great optical and mechanical properties. To improve the mechanical properties of PDMS, attention has been attracted to adding reinforcement materials to strengthen PDMS composites. Among all types of reinforcement materials, graphene (Gr) is ideal in that it demonstrates extremely high strength and rigidity. In addition, adding a small amount of Gr can significantly alter the mechanical properties of PDMS. Despite these benefits, voids and Gr-induced gaps commonly exist in Gr-reinforced composites. To reduce these problems, acoustic field (AF)-assisted inkjet printing has been proposed. Results show that the integration of the AF is beneficial for reducing voids and removing gaps between Gr flakes and the PDMS matrix. Due to these reasons, tensile properties and dynamic mechanical properties of Gr-reinforced PDMS composite are dramatically improved when the AF is integrated. In addition, AF can also improve the surface finish of inkjet-printed parts.

Production and Characterization of Graphene Oxide Surfaces against Uropathogens

Graphene and its functionalized derivatives have been increasingly applied in the biomedical field, particularly in the production of antimicrobial and anti-adhesive surfaces. This study aimed to evaluate the performance of graphene oxide (GO)/polydimethylsiloxane (PDMS) composites against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. GO/PDMS composites containing different GO loadings (1, 3, and 5 wt.%) were synthesized and characterized regarding their morphology, roughness, and hydrophobicity, and tested for their ability to inhibit biofilm formation under conditions that mimic urinary tract environments. Biofilm formation was assessed by determining the number of total and culturable cells. Additionally, the antibacterial mechanisms of action of GO were investigated for the tested uropathogens. Results indicated that the surfaces containing GO had greater roughness and increased hydrophobicity than PDMS. Biofilm analysis showed that the 1 wt.% GO/PDMS composite was the most effective in reducing S. aureus biofilm formation. In opposition, P. aeruginosa biofilms were not inhibited by any of the synthesized composites. Furthermore, 1% (w/v) GO increased the membrane permeability, metabolic activity, and endogenous reactive oxygen species (ROS) synthesis in S. aureus. Altogether, these results suggest that GO/PDMS composites are promising materials for application in urinary catheters, although further investigation is required.

On the deposition and polymorphism of CaCO3 crystals in the presence of the tetrapod-shaped ZnO nanomaterials and polydimethylsiloxane composite

The calcium carbonate (CaCO3) scale generated in water pipes and heat exchangers causes serious problems such as pipe blockage and corrosion. This study investigates the effect of the 4-to-10 μm-long and 350-to-700 nm centering-nucleus-wide ZnO tetrapod-like nanomaterials and polydimethylsiloxane composite (t-ZnO/PDMS) on deposition and polymorphism of CaCO3 crystals on the stainless-steel substrate. The results showed that the t-ZnO/PDMS coating inhibited CaCO3 depositions and represented an excellent antifouling coating. The weight-based inhibition efficiencies of CaCO3 deposition were up to 81.3% and 63.2% at 20 °C and 60 °C, respectively. The t-ZnO/PDMS coating also exhibited good inhibition in the presence of liquid flow. The inhibition is primarily because the very fine concave-convex microstructure of the t-ZnO/PDMS coated surface lowered the surface energy of the substrates, making it difficult for CaCO3 crystals to adhere to the surface. Also, metastable vaterite and aragonite precipitations were dominant in the t-ZnO/PDMS coated coupons at 20 °C and 60 °C, respectively, whereas the uncoated coupon exhibited calcite as the predominant polymorph in all the studied conditions. The t-ZnO/PDMS composite subject to the liquid flow made calcites distorted and framboidal vaterite aggregates, likely due to their mechanical effects. The inhibition of CaCO3 depositions is due to achieving hydrophobicity on substrate surfaces, changing preferential polymorph formation, and tailoring the morphology of the given polymorph by the t-ZnO/PDMS composite.

High-consistent optical fiber photoacoustic generator with carbon nanoparticles-PDMS composite

Optical fiber photoacoustic (PA) probe is considered to have great prospects in high resolution invasive imaging due to the advantages of flexible, miniaturized broadband ultrasonic excitation. Unfortunately, more attentions are currently focused on the fabrication of the PA probe with a high PA conversion efficiency, instead of the consistency of the developed probe that is of great importance for practical applications. In this paper, in consideration of the coating thickness and flatness closely concerned with the consistency, a number of PA probes with 15 wt.% carbon nanoparticles (CNPs) and polydimethylsiloxane (PDMS) composite were fabricated by a spin-transfer method with the help of transferring uniformly spin-coated film on the endface of an optical fiber. Underwater ultrasonic detection showed that the fabricated probes exhibited a good consistency with the corresponding lower coefficients of variation of 1.7%, 1.4% and 1.1% for the sound pressure, center frequency and bandwidth, sharply reduced by 89%, 72% and 81% in comparison with the commonly used dip-coating probes tested in this work. Also, due to the thinner film obtained through the presented fabrication method, the maximum PA pressure value of 1.04 MPa with a -6 dB bandwidth of 54.2 MHz was achieved, which further demonstrates a great potential in high-resolution ultrasound imaging utilizing multiple probes with high consistency.

Multifunctional modification of silk fabrics via a combination of sophora flower extract, phytic acid and silicone-containing organics: Flame retardancy, water repellency, antibacterial activity and ultraviolet resistance

Herein, a multifunctional composite coating is constructed on silk fabrics by a facile impregnation strategy. In detail, the pre-period involves the aggregation growth of sophora flower extract/phytic acid-lanthanum ion-silk fibroin complex network, while the post-period introduces a water repellent layer that is composed of hydroxyl-terminated polydimethylsiloxane and hexadecyltrimethoxysilane composite. Benefiting from the synergistic effect of P, Si and N elements, the optimized finished silk sample denoted as D/FR/WR-SF exhibits a limiting oxygen index value of up to 29.3%, and shows a damage length as low as 9.4 cm in the vertical burning test. Since the sophora flower extract contains flavonoids such as rutin and quercetin, it confers good antibacterial activity and ultraviolet resistance to silk fabrics. The results display that D/FR/WR-SF inhibits the colony propagation of Escherichia coli and Staphylococcus aureus, and achieves an ultraviolet protection factor value of 38.61 compared with the control silk fabrics. Attributed to the directional arrangement of long-chain alkane and Si-CH3, D/FR/WR-SF exhibits good water repellency with a water contact angle of 138°. Additionally, D/FR/WR-SF also presents satisfactory washing resistance (integrated properties after 25 laundering cycles). Therefore, such a complete multifunctional composite coating scheme shows great potential for expanding advanced textile applications.

Surface-modification of silver nanoparticle–based polydimethylsiloxane composite for fabrication of strain sensor

Composites consisting of surface-treated silver nanoparticles (AgNPs) in a polymer matrix were used to fabricate strain sensors. In order to ensure a good interaction of AgNPs with the polymer matrix in the composite, AgNPs were treated with 3-aminopropyltrimethoxysilane (APTMS). Silane-treated AgNPs (AM-AgNPs) contain, on their surface, an efficient coupling agent used in composites and as an adhesion promoter in adhesive formulation. The surface-treated conductive filler exhibits a good interaction with the PDMS matrix and improved composite performance, suggesting a good interface between AgNPs and the polymer matrix in the composite. AM-AgNPs were used as conductive filler in the composite, and an AM-AgNPs–based polydimethylsiloxane composite (AM-AgNPs@PDMS) strain sensor was fabricated via a drop-casting method. The surface morphology of the composite material and the electromechanical properties of the strain sensor were investigated. It was observed that both silane and amine groups were successfully grafted on the surface of the AgNPs, improving the dispersion and interfacial interaction in the PDMS matrix. The fabricated AM-AgNPs@PDMS composite strain sensor exhibited good electrical conductivity and sensing properties, measured as hysteresis behaviour until reaching 20% strain level; good sensitivity (Gauge Factor (GF) = 8.73 at 50% strain level); linearity (R2 = 0.9558); and good stability.

Tetris-Style Stacking Process to Tailor the Orientation of Carbon Fiber Scaffolds for Efficient Heat Dissipation

HighlightsCarbon fiber (CF) scaffolds with horizontally aligned, diagonally aligned and vertically aligned structure were fabricated via magnetic field-assisted Tetris-style stacking and carbonization process.The obtained CF scaffolds/ polydimethylsiloxane composites showed ultrahigh thermal conductivity (above 40 W m−1 K−1) in the fiber alignment direction.Fibers with different alignment direction can be combined by multiple stacking and carbonization process, allowing for the efficient heat transfer along customized paths.

Efficient Electromagnetic Interference Shielding of PPA6@NiM/PDMS Composites with Porous and Asymmetric Gradient Structures

In this work, magnetic PA6 microspheres (PPA6@NiM) with porous structures were prepared using the solvent co-precipitation method and electroless nickel plating technology, and the stacked magnetic microspheres were encapsulated with polydimethylsiloxane (PDMS) to obtain PPA6@NiM/PDMS composites. The existence of the porous structure increases the attenuation path of the electromagnetic wave, and the presence of the nickel layer improves the magnetic loss of the composite material to the electromagnetic wave and synergistically improves the absorption of the electromagnetic wave. Among them, the total shielding effectiveness (SET) of the PPA6@NiM4/PDMS composite is as high as 39.9 dB, and the reflection coefficient (R) is 0.83. To further increase the absorption effect of the composite material, an asymmetric gradient structure was constructed by utilizing the difference in electrical conductivity between the magnetic microspheres. The electromagnetic wave is incident from the surface with lower conductivity (impedance matching layer). It is reflected by the consistency with higher conductivity (strong reflective layer) than the bottom layer to increase the loss of electromagnetic waves inside the material. The composite SET constructed with M1 and M4 particles with the most significant difference in conductivity achieved 35.5 dB with an absorption coefficient (A) of 0.42. It shows that the porous combined asymmetric gradient structure we designed can effectively improve the shielding efficiency and absorption capacity of the composite material against electromagnetic microwaves and serve as a reference for creating high-absorbing and high-performance electromagnetic shielding materials.

Constructing highly flexible dielectric sponge for enhancing triboelectric performance

Functional materials that are with high dielectric constant are finding extensive applications in the conversion and storage of energy, which may also be the key for enhancing the output performance of triboelectric nanogenerator (TENG) by dielectrically modulating the charge trapping capability of the triboelectric interface. Here, CaCu3Ti4O12@BaTiO3 (CCTO@BT) is facilely synthesized for forming in polydimethylsiloxane (PDMS) layer. Due to the strengthened charge induction, the composite sponge with high flexibility and charge trapping capability is developed, and the polymeric sponge TENG (with 2 wt% CCTO@BaTiO3) demonstrates a high open-circuit voltage of 291.14 V, a short-circuit current of 35.49 µA, and a transfer charge quantity of 80 nC, which are far superior 206% higher than that are modulated by pure CCTO and 480% higher than pure PDMS (the short-circuit current). Dielectric enhancement mechanism was comparatively proved and demonstrated in the CCTO@BT/PDMS composites. To unravel the origin of the significantly enhanced triboelectric performance, permittivity and work function in the sponge were studied in-depth, and the strong internal polarization and potential barrier height were demonstrated. Moreover, the as-fabricated TENG can act as self-powered sensor for monitoring human motions, such as walking, jogging, and jumping ropes. This work provides a new insight into the unique potential of dielectric-modulated output enhancement strategy for unblocking the potential of TENG in energy harvesting and biophysical monitoring.

Flexible microwave absorbing composites based on polydimethylsiloxane filled with hybrid carbonaceous materials: Statistical analysis of the synergistic effect

AbstractThe effect of the combination of carbon nanotubes (CNT) and graphene nanoplatelets (GNP) on the electromagnetic absorbing properties of polydimethylsiloxane (PDMS) composites was investigated. Samples were prepared by a low‐cost and scalable simple one‐step blending approach. The number of experiments and sample compositions were optimized by design of experiments (DOE) technique, namely, Axial Simplex Centroid. The samples were analyzed concerning rheology, electric conductivity and electromagnetic properties, such as absorptivity (reflection loss – RL). CNT was revealed to be more efficient than GNP in structuring the conductive network of filler particles. On the other hand, the hybrid filler composite with a 1:1 ratio (CNT/GNP = 0.67%:0.67%) presented the highest electric conductivity (3.53 × 10−3 S m−1) and the best overall electromagnetic results, with measured RL reaching −25 dB and effective absorption bandwidth frequency of 4.6 GHz, with sample 2 mm thick. The best calculated RL value for this sample was observed with 2.5 mm with RL value corresponding to −46.8 dB. The special cubic polynomial model was successfully adjusted to the experimental data and statistically proved the synergistic effect of the hybrid on the electromagnetic properties of PDMS composites. Finally, PDMS/CNT/GNP composites were successfully prepared by a simple, fast and inexpensive method.