Metal-organic Framework Supported On Porous Polymer

The growth of continuous MOF membranes on porous polymeric supports is reported, wherein a dip-coating procedure is used to deposit a layer of seed MOF nanocrystals on the surfaces of porous polymers, preferably in the form of hollow fibers, and polycrystalline MOF membranes are subsequently grown at temperatures as low as 65°C. from precursor solutions. The present work opens the road to inexpensive and scalable fabrication of MOF membranes for large-scale separation applications.Georgia Tech Research Corporatio

Piezoelastic PVDF/TPU nanofibrous composite membrane: Fabrication and characterization

Poly (vinylidene fluoride) nanofibers (PVDF NFs) have been extensively used in energy harvesting applications due to their promising piezoresponse characteristics. However, the mechanical properties of the generated fibers are still lacking. Therefore, we are presenting in this work a promising improvement in the elasticity properties of PVDF nanofibrous membrane through thermoplastic polyurethane (TPU) additives. Morphological, physical, and mechanical analyses were performed for membranes developed from different blend ratios. Then, the impact of added weight ratio of TPU on the piezoelectric response of the formed nanofibrous composite membranes was studied. The piezoelectric characteristics were studied through impulse loading testing where the electric voltage had been detected under applied mass weights. Piezoelectric characteristics were investigated further through a pressure mode test the developed nanofibrous composite membranes were found to be mechanically deformed under applied electric potential. This work introduces promising high elastic piezoelectric materials that can be used in a wide variety of applications including energy harvesting, wearable electronics, self-cleaning filters, and motion/vibration sensors. - 2019 by the authors.The project was funded “partially” by Kuwait Foundation for the Advancement of Sciences under project code: PN17-35EE-02

Electrospun Nanomaterials

The papers collected in this Special Issue entitled “Electrospun Nanomaterials: Applications in Food, Environmental Remediation, and Bioengineering” illustrate the high diversity and potential for implementation of electrospun nanofibers in these fields, including the covering of a wide number of subtopics. Examples of these applications have included bioactive scaffolds, wound healing dressings, compound protective nanoreservoirs and sustained and controlled release systems. An important driver of these applications results from advances in materials science and new nanofiber manufacturing processes. Definitely, such pieces of fundamental research will contribute to the promotion of electrospinning as a focal point in the future development of technological applications at the interface of biological systems, which promise long-term benefits for both health and the environment

A study of the application of ultrasonic standing waves to the segregation of fine biological particles from liquids

This thesis describes research to evaluate the application of megahertz (1 to 10 MHz) ultrasonic standing waves to the segregation and separation of fine biological particles, in the size range of 0.1 to 10 μm, from liquids. Research has focused on the development of an alternative separation technique through the ability to selectively manipulate delicate, highly hydrated particles typical of many biological process streams where the sedimentation characteristics of the particles preclude traditional centrifugation-based separation methods and the requisite for non-invasive in line processing rules out filtration. A survey of both acoustic and ultrasonic research concentrating on the application of ultrasonic energy to processes involving biological particles has been carried out. An in-depth analysis of the theories of ultrasonics in relation to the stated aims of the work is presented in which the mechanisms controlling the migration of fine particles under the influence of a megahertz frequency standing wave field are discussed. Results of investigations to determine the feasibility of concentrating micron-sized particles in a standing wave field arc presented. These confirm that the small-scale separation of biological particles is achievable. The subsequent design of an experimental separation device and detailed experiments to elucidate the parameters of importance in determining the segregation of biological particles from liquids using this apparatus are described. Ultrasonic power input and fluid velocity were found to be the most critical process parameters and operational constraints as functions of particle size and ultrasonic frequency were identified. The design and development of a novel laser scanning technique for the monitoring of the migration of particles in an ultrasonic standing wave field is presented. Data obtained using this equipment has been used when discussing the design of large-scale continuous solid-liquid separation devices. Details of an ultrasonic system for the non-invasive, in-situ sample preparation of material for dynamic laser light scattering analysis of particle size distributions in the monitoring and control of bioprocesses are presented together with data from experimental trials. Results showed this to be a promising method for rapid and controlled sample preparation and well suited to handling process streams containing heterogeneous particle sizes. The thesis concludes by giving consideration to the necessary future work and to the application of the techniques described in the thesis to relevant biological separation problems

Sustainable innovation in membrane technologies for produced water treatment: Challenges and limitations

Discharged water from the oil and gas fields is a common type of wastewater called produced water (PW). It consists of different combinations of salinities, oils, and mineral deposits. Growing industrial demand, accelerated urbanization, and rapid population growth are putting enormous strain on the world?s water supply. Based on sustainable freshwater supplies, North Africa, the Middle East, and South Asia confront the ultimate water shortages threat. Proper implementation of innovative membrane technologies in wastewater treatment is considered a solution towards tackling water insecurity and sustainability. Different types of innovative membrane technologies used for produced water treatment were considered in this work. A framework of innovative membrane technology was studied for industrial wastewater with direct contribution to the environmental and economical sustainability factors, taking into consideration grand challenges and limitations in energy costs and environmental constraints. Treated produced water can be utilized in irrigation providing many benefits only if the desalination sector is mature and fully developed.Scopu

Piezoelastic PVDF/TPU Nanofibrous Composite Membrane: Fabrication and Characterization

Poly (vinylidene fluoride) nanofibers (PVDF NFs) have been extensively used in energy harvesting applications due to their promising piezoresponse characteristics. However, the mechanical properties of the generated fibers are still lacking. Therefore, we are presenting in this work a promising improvement in the elasticity properties of PVDF nanofibrous membrane through thermoplastic polyurethane (TPU) additives. Morphological, physical, and mechanical analyses were performed for membranes developed from different blend ratios. Then, the impact of added weight ratio of TPU on the piezoelectric response of the formed nanofibrous composite membranes was studied. The piezoelectric characteristics were studied through impulse loading testing where the electric voltage had been detected under applied mass weights. Piezoelectric characteristics were investigated further through a pressure mode test the developed nanofibrous composite membranes were found to be mechanically deformed under applied electric potential. This work introduces promising high elastic piezoelectric materials that can be used in a wide variety of applications including energy harvesting, wearable electronics, self-cleaning filters, and motion/vibration sensors

Development and evaluation of different electroactive poly(vinylidene fluoride) architectures for endothelial cell culture

Tissue engineering (TE) aims to develop structures that improve or even replace the biological functions of tissues and organs. Mechanical properties, physical-chemical characteristics, biocompatibility, and biological performance of the materials are essential factors for their applicability in TE. Poly(vinylidene fluoride) (PVDF) is a thermoplastic polymer that exhibits good mechanical properties, high biocompatibility and excellent thermal properties. However, PVDF structuring, and the corresponding processing methods used for its preparation are known to significantly influence these characteristics. In this study, doctor blade, salt-leaching, and electrospinning processing methods were used to produce PVDF-based structures in the form of films, porous membranes, and fiber scaffolds, respectively. These PVDF scaffolds were subjected to a variety of characterizations and analyses, including physicochemical analysis, contact angle measurement, cytotoxicity assessment and cell proliferation. All prepared PVDF scaffolds are characterized by a mechanical response typical of ductile materials. PVDF films displayed mostly vibration modes for the a-phase, while the remaining PVDF samples were characterized by a higher content of electroactive beta-phase due the low temperature solvent evaporation during processing. No significant variations have been observed between the different PVDF membranes with respect to the melting transition. In addition, all analysed PVDF samples present a hydrophobic behavior. On the other hand, cytotoxicity assays confirm that cell viability is maintained independently of the architecture and processing method. Finally, all the PVDF samples promote human umbilical vein endothelial cells (HUVECs) proliferation, being higher on the PVDF film and electrospun randomly-oriented membranes. These findings demonstrated the importance of PVDF topography on HUVEC behavior, which can be used for the design of vascular implants.This work has been partially funded by the Junta de Extremadura (Spain), the Spanish Ministry of Science and Innovation, the European Social Fund, the European Regional Development Fund, and the European Next Generation Funds (Grant Numbers PD18077, TA18023, and GR21201). The authors also thanks to Portuguese Foundation for Science and Technology (FCT) for financial support under grants SFRH/BD/140698/2018 (RP), 2020.04163. CEECIND (CR). The also authors acknowledge funding by Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID 2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry Departments under the ELKARTEK program