Magnetic properties of acrylic UV-cured films containing magnetite nanoparticles

2011 ◽  
Vol 1312 ◽  
Author(s):  
Alessandro Chiolerio ◽  
Paolo Allia ◽  
Paola Tiberto ◽  
Lorenza Suber ◽  
Giada Marchegiani ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetite Nanoparticles ◽  
Uv Light ◽  
Uv Curing ◽  
Magnetic Interactions ◽  
Gradient Force ◽  
Radical Chain ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Ft Ir

ABSTRACTAcrylic based films containing thermo-chemically synthesized magnetite nanoparticles (NPs) were prepared by UV-curing. A stable dispersion of Fe3O4 NPs in n-hexane was added to polyethylene glycol diacrylate (PEGDA) oligomer or to hexanediol diacrylate (HDDA) oligomer, producing a blend whose viscosity matches the processing requirements for inkjet printing technology. Morphologic characterization is provided by means of Field Effect SEM on a representative nanocomposite section.By real-time FT-IR analysis it was shown that Fe3O4 NPs are able to initiate radical chain-grown polymerization under UV light, for what concerns the HDDA matrix. Tight cross-linked transparent polymeric films were obtained after 1 minute of UV irradiation.The magnetic properties of the produced films were studied by means of an Alternating-Gradient Force Magnetometer (AGFM) in the temperature range 10 – 300 K and up to 18 kOe. The isothermal magnetization curves of both HDDA and PEGDA -based nanocomposites showed that these hybrid systems must be described as interacting superparamagnets (ISP) characterized by inter-particle magnetic interactions dominating over intra-particle effects.

Fabrication of PEG Hydrogel and PDMS Microstructures by a Simple UV Curing Process for Nanobio-Chip Applications

2014 ◽  
Vol 941-944 ◽  
pp. 404-410 ◽  
Author(s):  
Young Ho Kim ◽  
Jeong Woo Sohn ◽  
Youngjae Woo ◽  
Joo Hyun Hong ◽  
Juyoung Park
Keyword(s):  
Polyethylene Glycol ◽  
Uv Irradiation ◽  
Large Scale ◽  
Uv Light ◽  
Single Step ◽  
Polydimethyl Siloxane ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Metal Mask ◽  
Glass Chip

Polyethylene glycol (PEG) hydrogel microstructures with various shapes and sizes on a glass chip were prepared by a simple and rapid ultraviolet (UV) irradiation method using a metal mask. Photocurable PEG solution prepared by mixing 95 wt.% polyethylene glycol diacrylate and 5 wt.% 2-hydroxy-2-methylpropiophenone as a photo-initiator was injected to the gap between bottom and upper glasses in a simply assembled glass chip. After a metal mask with line-and-space or complex patterns was placed on the glass chip, UV light from a spot UV irradiation device was exposed to the glass chip through the metal mask for 7 seconds at UV intensity of 26 mW/cm2. Then the PEG hydrogel micropatterns on the glass chip were obtained after removing unreacted PEG solution by air blowing. To prepare more rigid microstructure, the prepared PEG micropatterned chip was exposed under UV light for 20 seconds. Then the PEG hydrogel micropattern chip was fabricated by a simple and rapid procedure. Micropattern transferring was performed from the PEG hydrogel chip to polydimethyl siloxane (PDMS) replica by a solution casting. The prepared micropatterned PDMS replicas showed similar shape and size of microstructures compared to that of the corresponded PEG hydrogel chip. Thus the PEG hydrogel microstructures on a glass chip could be used as a mold to fabricate micropattern PDMS chips for nanobio-chip applications. Furthermore, the present method provides large scale chip fabrication, more than 4 cm-length and 4 cm-width in a single step, not only PEG hydrogel chips but also PDMS chips.

The Effect of Polyethylene (Glycol) Diacrylate Post-Fabrication Rest Time on Compressive Properties

2017 ◽  
Author(s):  
Ozlem Yasar ◽  
Serkan Inceoglu ◽  
Ramesh Prashad
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Uv Light ◽  
Ageing Time ◽  
Solidification Process ◽  
Ease Of Use ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Porous Microstructure ◽  
Rest Time

In recent years, tissue engineering has been utilized as an alternative approach for the organ transplantation. The success rate of tissue regeneration is influenced by the type of biomaterials, cell sources, growth factors and scaffold fabrication techniques used. The poly(ethylene glycol) diacrylate (PEGDA) is one of commonly used biomaterials because of its biocompatibility, ease of use, and porous microstructure. The mechanical properties of PEGDA have been studied to some extent by several research groups. However, the stability of the mechanical properties with time has not been investigated. In this research, we studied how the mechanical properties of different concentrations of PEGDA change with the post-fabrication ageing time. Cylindrical PEGDA samples were prepared 20%, 40%, 60%, 80%, and 100% concentrations and cured under the UV light. After the solidification process, weight of each sample was monitored in every 0, 2, 4, 6, and 24 hours post-fabrication ageing time until the mechanical testing. Compressive elastic modulus and strength were calculated and statistically analyzed. Our results indicated that the water content of each PEGDA group constantly decreased by time, however, this loss significantly affected the elastic modulus and strength only after 6 hours in some PEGDA concentration.

Preparation of Microstructure Molds of Montmorillonite/Polyethylene Glycol Diacrylate and Multi-Walled Carbon Nanotube/Polyethylene Glycol Diacrylate Nanocomposites for Miniaturized Device Applications

2015 ◽  
Vol 15 (10) ◽  
pp. 7860-7865
Author(s):  
Young Ho Kim ◽  
Jeong-Woo Sohn ◽  
Youngjae Woo ◽  
Joo-Hyun Hong ◽  
Gyu Man Kim ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Carbon Nanotube ◽  
Uv Curing ◽  
Optical Microscope ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Multi Walled Carbon Nanotube ◽  
Medical Diagnostic ◽  
Device Applications ◽  
Uv Curing Process

Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices.

Multi Material 3D Scaffold Printing with Maskless Photolithography

MRS Advances ◽  
2017 ◽  
Vol 2 (24) ◽  
pp. 1303-1308
Author(s):  
Joyce Tam ◽  
Ozlem Yasar
Keyword(s):  
Tissue Engineering ◽  
Organ Transplantation ◽  
Uv Light ◽  
Layer By Layer ◽  
3D Scaffold ◽  
Liquid Form ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Short Period ◽  
The Right

ABSTRACTIn today’s technology, organ transplantation is found very challenging as it is not easy to find the right donor organ in a short period of time. In the last several decades, tissue engineering was rapidly developed to be used as an alternative approach to the organ transplantation. Tissue engineering aims to regenerate the tissues and also organs to help patients who waits for the organ transplantation. Recent research showed that in order to regenerate the tissues, cells must be seeded onto the 3D artificial laboratory fabricated matrices called scaffolds. If cells show healthy growth within the scaffolds, they can be implanted to the injured tissue to do the regeneration. One of the biggest limitation that reduces the success rate of tissue regeneration is the fabrication of accurate thick 3D scaffolds. In this research “maskless photolithography” was used to fabricate the scaffolds. Experiment setup consist of digital micro-mirror devices (DMD) (Texas Instruments, DLi4120), optical lens sets, UV light source (DYMAX, BlueWave 200) and PEGDA which is a liquid form photo-curable solution. In this method, scaffolds are fabricated in layer-by-layer fashion to control the interior architecture of the scaffolds. Working principles of the maskless photolithography is, first layer shape is designed with AutoCAD and the designed image is uploaded to the DMD as a bitmap file. DMD consists of hundreds of tiny micro-mirrors. When the UV light is turned on and irradiated the DMD, depending on the micro-mirrors’ angles, UV light is selectively reflected to the low percentage Polyethylene (glycol) Diacrylate (PEGDA) photo-curable solution. When UV light penetrates into the PEGDA, only the illuminated part is solidified and non-illuminated area still remains in the liquid phase. In this research, scaffolds were fabricated in three layers. First layer and the last layer are solid layers and y-shape open structure was sandwiched between these layers. After the first layer is fabricated with DMD, a “y-shape” structure was fabricated with the 3D printer by using the dissolvable filament. Then, it was placed onto the first solid layer and covered with fresh high percentage PEGDA solution. UV light was reflected to the PEGDA solution and solidified to make the second and third layers. After the scaffold was fabricated, it is dipped into the limonene solution to dissolve the y-shape away. Our results show that thick scaffolds can be fabricated in layer-by-layer fashion with “maskless photolithography”. Since the UV light is stable and does not move onto the PEGDA, entire scaffold can be fabricated in one single UV shot which makes the process faster than the current fabrication techniques.

Compressive Evaluation of Polyethylene (Glycol) Diacrylate (PEGDA) for Scaffold Fabrication

2016 ◽  
Author(s):  
Ozlem Yasar ◽  
Serkan Inceoglu
Keyword(s):  
Mechanical Properties ◽  
Uv Light ◽  
Ultra Violet ◽  
Precursor Solution ◽  
Building Blocks ◽  
The Body ◽  
Compression Tests ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Water Ratio

In the field of tissue engineering, scaffold is the foundation structure that provides the desired mechanical support for the tissue being engineered, surface for cells to attach and spread, and access for nutrient transport crucial for cell viability. The scaffolds are 3D building blocks which are designed and fabricated precisely prior to its implantation to the host tissue. When scaffolds with desired shape and size are fabricated, they can be seeded with cells and appropriate growth factors. After cells show healthy growth within the scaffold, they are implanted into the body with the scaffold to allow full-scale tissue regeneration. In this research, photolithography is adapted as a fabrication method to generate PEGDA-based structures. In this method, ultra-violet (UV) light is reflected on PEGDA and as a result of the interaction between UV light and precursor solution, PEGDA turns into solid form. Despite the potential of PEGDA in scaffold applications, the mechanical properties have not been studied in a great extent. Therefore, in this project, the mechanical characterization of PEGDA was conducted for various polymer concentrations. Specimens with 20%, 40%, 60%, 80% and 100% PEGDA to water ratio were prepared for compression tests. Our preliminary experimental data results show that, mechanical properties of PEGDA can be controlled by changing the PEGDA to water ratio. Stronger and stiffer structures can be obtained with high PEGDA concentrations while softer structures can be fabricated with reduced PEGDA concentrations.

Magnetic properties of bacterial magnetosomes and chemosynthesized magnetite nanoparticles

2008 ◽  
Vol 44 (2) ◽  
pp. 113-120 ◽  
Author(s):  
M. Timko ◽  
A. Dżarová ◽  
V. Závišová ◽  
M. Koneracká ◽  
A. Šprincová ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetite Nanoparticles

scholarly journals Elucidating the Molecular Mechanisms for the Interaction of Water with Polyethylene Glycol-Based Hydrogels: Influence of Ionic Strength and Gel Network Structure

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 845
Author(s):  
Xin Yang ◽  
Bronwin Dargaville ◽  
Dietmar Hutmacher
Keyword(s):  
Polyethylene Glycol ◽  
Ionic Strength ◽  
Molecular Mechanisms ◽  
Repeat Unit ◽  
Bound Water ◽  
Weight Fraction ◽  
Swelling Ratio ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Hydrogel System

The interaction of water within synthetic and natural hydrogel systems is of fundamental importance in biomaterial science. A systematic study is presented on the swelling behavior and states of water for a polyethylene glycol-diacrylate (PEGDA)-based model neutral hydrogel system that goes beyond previous studies reported in the literature. Hydrogels with different network structures are crosslinked and swollen in different combinations of water and phosphate-buffered saline (PBS). Network variables, polyethylene glycol (PEG) molecular weight (MW), and weight fraction are positively correlated with swelling ratio, while “non-freezable bound water” content decreases with PEG MW. The presence of ions has the greatest influence on equilibrium water and “freezable” and “non-freezable” water, with all hydrogel formulations showing a decreased swelling ratio and increased bound water as ionic strength increases. Similarly, the number of “non-freezable bound water” molecules, calculated from DSC data, is greatest—up to six molecules per PEG repeat unit—for gels swollen in PBS. Fundamentally, the balance of osmotic pressure and non-covalent bonding is a major factor within the molecular structure of the hydrogel system. The proposed model explains the dynamic interaction of water within hydrogels in an osmotic environment. This study will point toward a better understanding of the molecular nature of the water interface in hydrogels.

scholarly journals Quantitative mapping of magnetic properties at the nanoscale with bimodal AFM

Nanoscale ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 2026-2033
Author(s):  
Victor G. Gisbert ◽  
Carlos A. Amo ◽  
Miriam Jaafar ◽  
Agustina Asenjo ◽  
Ricardo Garcia
Keyword(s):  
Magnetic Properties ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Magnetic Interactions ◽  
Quantitative Mapping ◽  
Quantitative Accuracy

We demonstrate that a force microscope operated in a bimodal configuration enables the mapping of magnetic interactions with high quantitative accuracy and high-spatial resolution (∼30 nm).

scholarly journals Generation of Photopolymerized Microparticles Based on PEGDA Using Microfluidic Devices. Part 1. Initial Gelation Time and Mechanical Properties of the Material

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 293
Author(s):  
José M. Acosta-Cuevas ◽  
José González-García ◽  
Mario García-Ramírez ◽  
Víctor H. Pérez-Luna ◽  
Erick Omar Cisneros-López ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Gelation Time ◽  
Mesh Size ◽  
Microfluidic Devices ◽  
Future Generation ◽  
Mechanical Tests ◽  
Continuous Systems ◽  
Polyethylene Glycol Diacrylate ◽  
Glycol Diacrylate ◽  
Close Relationship

Photopolymerized microparticles are made of biocompatible hydrogels like Polyethylene Glycol Diacrylate (PEGDA) by using microfluidic devices are a good option for encapsulation, transport and retention of biological or toxic agents. Due to the different applications of these microparticles, it is important to investigate the formulation and the mechanical properties of the material of which they are made of. Therefore, in the present study, mechanical tests were carried out to determine the swelling, drying, soluble fraction, compression, cross-linking density (Mc) and mesh size (ξ) properties of different hydrogel formulations. Tests provided sufficient data to select the best formulation for the future generation of microparticles using microfluidic devices. The initial gelation times of the hydrogels formulations were estimated for their use in the photopolymerization process inside a microfluidic device. Obtained results showed a close relationship between the amount of PEGDA used in the hydrogel and its mechanical properties as well as its initial gelation time. Consequently, it is of considerable importance to know the mechanical properties of the hydrogels made in this research for their proper manipulation and application. On the other hand, the initial gelation time is crucial in photopolymerizable hydrogels and their use in continuous systems such as microfluidic devices.

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