Browsing by Subject "PVDF"

Now showing 1 - 7 of 7

Access status: Open Access ,
Comparative Analysis of Electrophoretic Deposition and Dip Coating for Enhancing Electrical Properties of Electrospun PVDF Mats Through Carbon Nanotube Deposition
(2025) Kopacz, Michał; Szewczyk, Piotr K.; Długoń, Elżbieta; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Integrating carbon nanotubes (CNTs) into electrospun polyvinylidene fluoride (PVDF) fibers is a promising approach for developing conductive and multifunctional materials. This study systematically compared two CNT deposition techniques, electrophoretic deposition (EPD) and dip coating (DC), in terms of their effectiveness in modifying the surface of aligned electrospun PVDF mats. Morphological characterization revealed that EPD produced more homogeneous and compact CNT coatings. In contrast, DC resulted in discontinuous and irregular layers regardless of deposition time. A key distinction between the two methods was the tunability of the coating: EPD allowed for precise control over CNT layer thickness and mass accumulation by adjusting the deposition time. In contrast, DC showed no significant changes in thickness with longer immersion. These structural differences translated into distinct electrical behaviors. Resistance measurements showed that EPD samples exhibited a substantial decrease in resistance with increasing deposition time, from 5.9 ± 2.5 kΩ to 0.2 ± 0.1 kΩ, indicating the formation of well-connected conductive pathways. On the other hand, DC samples maintained relatively constant, higher resistance values across all conditions. Additionally, EPD-coated mats demonstrated enhanced touch sensitivity, generating higher and more stable current responses compared to DC-deposited samples. These results confirm that EPD is a more effective, tunable method for fabricating conductive CNT coatings on electrospun PVDF mats, particularly for applications in flexible electronics and wearable sensors.
Access status: Open Access ,
Hybrid piezo-, pyro-, and triboelectric nanogenerator based on PVDF and rGO composite fibers for a multifunctional approach to energy harvesting applications
(2025) Sukumaran, Sunija; Szewczyk, Piotr K.; Bajda, Tomasz; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Recently, wearable nanogenerators have gained interest in energy harvesting and sensors, driven by smart electronics and Internet of Things (IoT) advancements. Here, we have developed a multifunctional nanogenerator that can convert mechanical and thermal energy into electrical energy via piezoelectric, triboelectric, and pyroelectric effects. The electrospun nanogenerator was fabricated to investigate the effect of reduced graphene oxide (rGO) on the energy generation of polyvinylidene fluoride (PVDF) fibers. The highest amount of electroactive β phase (81 %) and crystallinity (48.58 %) were obtained for 7 wt% rGO/PVDF fiber composite. Then, the 7 wt% rGO/PVDF composite was taken to prepare the piezo, tribo, and pyroelectric nanogenerator, and characterized using piezoresponse force microscopy (PFM), Kelvin probe microscopy (KPFM), and scanning thermal microscopy (SThM). Furthermore, the nanogenerator was made using the composite mat, illustrating its potential for powering small electronic devices using piezoelectric power and an enormous triboelectric power density of 3.37 ± 0.72 mWcm−2. We also demonstrate the device’s multifunctionality under thermal fluctuations. The results show the synergetic tribo and pyroelectric current of 33nA from 7 wt% rGO/PVDF. The present work indicates the significance of rGO inclusion into a PVDF matrix, resulting in enhanced multifunctional properties for energy harvesting, thereby enabling self-powering capabilities for microelectronic devices.
Access status: Open Access ,
Multifunctional piezoelectric yarns and meshes for efficient fog water collection, energy harvesting, and sensing
(2024) Parisi, Gregory; Szewczyk, Piotr K.; Narayan, Shankar; Ura, Daniel Paweł; Knapczyk-Korczak, Joanna; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Given global water scarcity and the quest for sustainable energy, there's a pressing need for integrated approaches addressing water-energy interdependence worldwide. A practical approach for this challenge involves the implementation of fog water collectors. Herein, a polyvinylidene fluoride (PVDF) multifunctional device capable of harvesting water and electricity from wind is developed and tested, collecting up to 365 mg cm−2 h−1 of fog water. Due to the piezoelectric nature of electrospun PVDF, these yarns and meshes not only serve as piezoelectric sensors, enabling the detection of incoming fog flow and determination of its speed and, bust also harvest electricity by charging a capacitor, making it a green and renewable power source. In this study, promising insights are offered into developing efficient fog water collection methods and utilizing piezoelectric fiber-based yarns and meshes for multifunctional applications in sustainable water management, energy harvesting, and sensing in a single device.
Access status: Open Access ,
Multifunctional, Flexible and Interactive PVDF Fibers with Tunable Conductivity via CNT Coatings for Sensing and Smart Textile Applications
(2025) Kopacz, Michał; Szewczyk, Piotr K.; Długoń, Elżbieta; Berniak, Krzysztof; Nizioł, Jacek; Jeleń, Piotr; Sitarz, Maciej; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Integrating electronics into textiles has the potential to revolutionize wearable devices, but achieving conductivity without compromising breathability and flexibility remains a challenge. Electrospun polyvinylidene fluoride (PVDF) fibers offer a porous and flexible scaffold but are inherently insulating. Previous methods for adding conductivity often reduce vapor permeability and mechanical performance. Here, this study reports a two-step fabrication strategy using electrophoretic deposition (EPD) of carbon nanotubes (CNTs) onto electrospun PVDF fibers, resulting in highly conductive (80 $\pm$ 6 $\Omega$), porous, and stretchable mats (elongation of ≈600%). The EPD process enables tunable conductivity while preserving fiber structure and water vapor transmission. The mats achieve significantly lower impedance and enhanced mechanical performance compared to existing coatings. This study demonstrates the use of these composites as sensors capable of detecting pressure, motion, respiration, and temperature. This multifunctionality, combined with scalable fabrication, highlights their potential in smart textiles. These findings open new opportunities for designing wearable sensors that unite functionality, user comfort, and durability.
Access status: Open Access ,
Optimizing Piezoelectric Coefficient in PVDF Fibers: Key Strategies for Energy Harvesting and Smart Textiles
(2023) Sukumaran, Sunija; Szewczyk, Piotr K.; Knapczyk-Korczak, Joanna; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
With the advancement in smart electronic devices and self-powered devices, the demand for piezoelectric polymers found potential research interest. Among these, electrospun polyvinylidene fluoride (PVDF) fibers have gained attention for energy harvesting due to their flexibility and higher piezoelectric coefficient. We compare various methods to enhance PVDF's piezoelectric properties, including different solvents (DMAc, DMF), conductive filler (rGO), and annealing as post-treatment. Our results indicate that PVDF/rGO fibers in DMAc solvent exhibit the highest β phase fraction and crystallinity. Moreover, for the first time, we present the piezoelectric properties of PVDF/rGO electrospun single fiber using high voltage switching spectroscopy piezoelectric force microscopy (HVSS-PFM). The highest piezoelectric coefficient (d33) was measured for PVDF/DMAc-rGO composite fibers. Notably, PVDF/rGO in DMAc solvent significantly improves the piezoelectric coefficient, leading to a remarkable fourfold increase in power density compared to pure PVDF, making it a promising material for energy harvesting applications.
Access status: Open Access ,
Photoresponsive Electrospun Fiber Meshes with Switchable Wettability for Effective Fog Water Harvesting in Variable Humidity Conditions
(2023) Parisi, Gregory; Szewczyk, Piotr K.; Narayan, Shankar; Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
The global water supply worsens yearly with climate change; therefore, the need for sustainable water resources is growing. One of them is fog water collectors with variable surface wettability, with multifunctional designs for utilization worldwide and to address regions with low humidity levels. Therefore, we created fiber meshes with a photoresponsive switchable surface. This study uses electrospun polyvinylidene fluoride (PVDF) meshes, whose wettability is controlled by adding $TiO_{2}$. The fog water collection performance is studied at high and low humidity levels. With $TiO_{2}-PVDF$, the electrospun mesh can be converted from hydrophobic to hydrophilic under UV irradiation and transformed back to a hydrophobic state with heat treatment. The switchable meshes were found to be more effective at water collection after UV irradiation at lower fog rates of 200 $mL·h^{–1}$. The ability to switch between hydrophobic and hydrophilic properties as needed is highly desired in fog collection applications using electrospun meshes, as it can improve overall efficiency after UV irradiation.
Access status: Open Access ,
Wettability gradient of photoresponsive electrospun yarns for harp-based fog water harvesting
(2024) Parisi, Gregory; Szewczyk, Piotr K.; Narayan, Shankar; Stachewicz, Urszula
WIMiIP
Fog water harvesting offers a solution to water scarcity. Here, we introduce a method to enhance fog water harvesting systems utilizing electrospun yarns featuring a wettability gradient. These yarns, made from polyvinylidene fluoride (PVDF) and titanium dioxide (TiO2), gain photoinduced hydrophilicity under UV light due to TiO2 photocatalytic properties, allowing dynamic shifts from hydrophobic to hydrophilic states. Experiments show that an alternating PVDF-TiO2 harp with a wettability gradient surpasses purely hydrophobic or hydrophilic versions in fog collection. The strategic mix of hydrophobic and hydrophilic sections enhances droplet movement and water capture, achieving a 16% increase in collection rate up to 400 mg cm−2 h−1. This approach introduces a novel method for creating wettability gradients in electrospun yarns via UV irradiation and represents a significant advancement in adaptable fog water harvesting systems.