Incorporation Of Polyethylene Glycol Research Articles

Biodegradable electrospun poly(L-lactide-co-ε-caprolactone)/polyethylene glycol/bioactive glass composite scaffold for bone tissue engineering.

The field of tissue engineering has witnessed significant advancements in recent years, driven by the pursuit of innovative solutions to address the challenges of bone regeneration. In this study, we developed an electrospun composite scaffold for bone tissue engineering. The composite scaffold is made of a blend of poly(L-lactide-co-ε-caprolactone) (PLCL) and polyethylene glycol (PEG), with the incorporation of calcined and lyophilized silicate-chlorinated bioactive glass (BG) particles. Our investigation involved a comprehensive characterization of the scaffold's physical, chemical, and mechanical properties, alongside an evaluation of its biological efficacy employing alveolar bone-derived mesenchymal stem cells. The incorporation of PEG and BG resulted in elevated swelling ratios, consequently enhancing hydrophilicity. Thermal gravimetric analysis confirmed the efficient incorporation of BG, with the scaffolds demonstrating thermal stability up to 250°C. Mechanical testing revealed enhanced tensile strength and Young's modulus in the presence of BG; however, the elongation at break decreased. Cell viability assays demonstrated improved cytocompatibility, especially in the PLCL/PEG+BG group. Alizarin red staining indicated enhanced osteoinductive potential, and fluorescence analysis confirmed increased cell adhesion in the PLCL/PEG+BG group. Our findings suggest that the PLCL/PEG/BG composite scaffold holds promise as an advanced biomaterial for bone tissue engineering.

Blended Membrane of Polyethylene‐Glycol‐Grafted‐PIM‐1 and Tröger's Base Polymer for the Separation of Pentose and Hexose

AbstractMonosaccharides are vital building blocks in bioengineering applications; however, their extraction from intricate mixtures is challenging and uses substantial amounts of energy. Polymers of intrinsic microporosity (PIMs) offer an innovative avenue for separating monosaccharides. We modified PIM‐1membranes to improve the glucose/xylose separation by incorporating polyethylene glycol monomethyl ether (mPEG). The optimal mPEG (molecular weight: 1000 Da; mass fraction: 2.5 %; solvent: methanol) delivered a xylose separation coefficient of 2.62. With the hybrid membrane of PIM‐1‐mPEG (50 w.t.%) and hydrophilic Tröger's base polymerer (DMBP‐TB, 50 w.t.%), the separation factor for xylose/glucose in an aqueous solution was 2.51 for single‐stage running and 11.32 after five‐stage running. There are large fractions of micropores for PIM‐1‐mPEG, and there is difference on solute‐membrane interactions for pentose/hexose, which are regarded to be the main driving force for the high pentose/hexose selectivity in methanol. The blending of PIM‐1‐mPEG and DMBP‐TB, integrates the microporosity and hydrophilicity, finally endues the high pentose/hexose selectivity in aqueous solution. These microporous membranes are promising materials for efficiently separating monosaccharides and jnl> small organic molecules while minimizing energy consumption. We established a solid foundation for further exploring microporous membranes for various applications, notably in bioengineering.

Double in-situ lignin modification in surfactant-assisted glycerol organosolv pretreatment of sugarcane bagasse towards efficient enzymatic hydrolysis

Organosolv pretreatment effectively fractionates lignocellulosic biomass for efficient enzymatic hydrolysis, yielding fermentable sugars. However, substantial lignin redeposition on the substrate surface and residual lignin content exacerbate lignin’s inhibitory effects on subsequent enzymatic hydrolysis. An in-situ lignin modification is proposed to address this challenge by incorporating polyethylene glycol (PEG) series into glycerol organosolv (GO) pretreatment. According to the results obtained, PEG-assisted GO pretreated substrate exhibited significantly increased sugar yield during enzymatic hydrolysis, particularly with PEG 4000, showing 35.4% higher glucose yield over 72 h. The improved glucose yield with PEG could be attributed to changes in the physicochemical structure and properties of residual lignin, mitigating its non-productive interaction with cellulase enzymes. PEG's presence in GO pretreatment also increased β-O-4 linkages preservation by 55% and reduced phenolic hydroxyl groups by 28% in lignin fragments versus no surfactants. This outcome resulted from introducing glycerol and PEG hydroxyl tails into the lignin structure, forming α-etherified lignin and rendering it more hydrophilic. Simulations confirmed strong Van Der Waals and hydrogen bonding interactions between lignin units and PEG, hindering lignin fragments repolymerization. Incorporating PEG in the organosolv pretreatment proves highly beneficial for cellulase-mediated lignocellulosic biorefinery, resembling a lignin-first strategy. The optimized process enables efficient biomass utilization for sustainable fuels and chemicals production.

Synthesis and characterization of an innovative sodium alginate/flaxseed gum green hydrogel for forward osmosis desalination

Recently, fresh water resources have been limited globally. Thus, desalination has been the most recommended solution to overcome this issue. Forward osmosis (FO) is an affordable and developing desalination technique. In this current study, a cutting-edge green hydrogel was prepared from a polymer blend of flaxseed gum (FG) and sodium alginate using epichlorohydrin (ECH) as a crosslinker and polyethylene glycol (PEG) as a semi-interpenetrating network polymer. The impact of PEG incorporation on the hydrogel’s response was investigated, and the influence of different mass contents of FG and ECH on the swelling measurements of the hydrogel was studied to optimize the composition of the hydrogel. The optimum hydrogel was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction and the compressive strength test. Furthermore, the behavior of the present hydrogel was examined as a draw agent in a batch FO unit. The water flux and the reverse solute flux were measured at various values of average hydrogel particle size and feed solution (FS) temperature and concentration. The optimal hydrogel of 0.3 PEG/polymer blend mass ratio, 12% FG, and 0.95 ECH/polymer blend mass ratio exhibits a swelling ratio (%) of 1800 after an hour and an equilibrium swelling ratio (ESR) (%) of 5300. The results of the FO experiments revealed that raising FS temperature and reducing FS concentration and average hydrogel particle size enhance water flux.

Plastic composite of bamboo charcoal stabilized polyethylene glycol with thermal energy storage and temperature regulation for building energy efficiency

AbstractPhase change materials (PCMs) are often used as building materials to reduce the energy consumption. However, conventional PCMs are susceptible to leakage and have a short service life. To solve this problem, thermal energy storage (TES) composites were fabricated by using bamboo charcoal (BC) encapsulating polyethylene glycol (PEG) as the PCM and low density polyethylene (LDPE) as the matrix. The shape and structure of BC and BC‐plastic composites were examined using scanning electron microscopy, X‐ray diffractometry, and mercury intrusion porosimetry. Differential scanning calorimetry, thermogravimetry (TG), and infrared thermography were used to characterize the manufactured TES composites. Physical and mechanical strength assessments were also conducted. The results demonstrated that: (1) BC possessed a rich void structure with a porosity of 61.4%, which could be used to adsorb PEG and the composites was a combination of PEG, BC, and LDPE with no chemical reaction; (2) thermal tests demonstrated that the composites exhibited favorable temperature regulation properties, featuring a maximum latent heat capacity of 29.1 J/g along with suitable phase change temperatures, yet thermal durability needs to be improved much further, addition of PEG reduced thermal conductivity of the composite from 0.38 to 0.34 W/mK; (3) the addition of PEG was beneficial for the impact strength but had a negative impact on the flexural and tensile properties; and (4) due to their satisfactory thermal performance and acceptable mechanical properties, these TES composites can be effectively utilized as building materials for temperature control purposes.Highlights Bamboo charcoal (BC) had a large number of pores that can encapsulate polyethylene glycol (PEG). PEG/BC performed satisfactory latent heat. Low density polyethylene was used as the matrix to realize the second encapsulation of phase change material. Thermal energy storage composites had excellent stability and good heat storage capacity. PEG incorporation negatively affected flexural and tensile properties.

Improvement of the mechanical and shape memory properties in polylactide/polyethylene glycol blends by reactive graphene oxide

The widespread application of biodegradable polylactide (PLA) is hindered by its brittleness. Polyethylene glycol (PEG) is commonly utilized as a plasticizer because of its favorable compatibility with PLA. However, the incorporation of PEG considerably diminishes the tensile strength of PLA. To address this issue, reactive isocyanate-modified graphene oxide (mGO) was synthesized and used as an enhancer in PLA/PEG blends. By virtue of the reaction between the isocyanate group in mGO and the terminal hydroxyl groups of PLA and PEG, graphene-based polyurethane (PU) in-situ formed and enhanced the interface between GO and the matrix. Consequently, the PLA/PEG/mGO composites exhibit simultaneously improved tensile and impact strengths, achieving an increase of 20.6% and 29.4%, respectively, compared to PLA/PEG blends. Moreover, the in situ formed PU reduces the relaxation time of the molecule motion and improved the entanglement density, thereby improving the shape-memory recovery rate and final recovery degree of the composites. This work provides a facile method to simultaneously improve the dispersion of GO and enhance its interface with polymer, thereby supplying well comprehensive properties of PLA and extending the applications of biodegradable polymers.

Cerasome Versus Liposome: A Comparative Pharmacokinetic Analysis Following Intravenous Administration into Rats.

Cerasomes, due to their external siloxane network, demonstrate markedly higher physicochemical stability and, therefore, easier handling and storage than liposomes. The main objective of this study was to compare the pharmacokinetics (PK) of cerasome and liposome following intravenous administration. The PK of PEGylated and non-PEGylated cerasomes was also compared to see whether the presence of a hydrophilic siloxane network on the surface of cerasomes can play the role of polyethylene glycol (PEG) in increasing the blood circulation of these vesicles. Silver sulfide (Ag2S) quantum dots (Qds)-loaded PEGylated and non-PEGylated cerasomes and PEGylated liposomes were fabricated and thoroughly characterized in terms of particle size, polydispersity index, zeta potential, entrapment efficiency, and in vitro stability. For pharmacokinetic evaluation, the free Qds and the selected formulations were intravenously injected into rats, and blood samples were collected for up to 72 hours. Pharmacokinetic parameters were calculated by the non-compartmental method. Both cerasomal and liposomal carriers significantly improved the PK of Qds. For example, the elimination half-life (t1/2) and the area under the plasma concentration-time curve from time 0 to time infinity (AUC0-∞) for the free Qds were 4.39 h and 8.01 µg/mL*h and for cerasomal and liposomal formulations were 28.82 versus 26.95 h and 73.25 versus 62.02 µg/mL*h, respectively. However, compared to each other, the plasma concentration-time profiles of PEGylated cerasomes and liposomes displayed similar patterns, and the statistical comparison of their pharmacokinetic parameters did not show any significant difference between the two types of carriers. For PEGylated cerasomes, t1/2 and AUC0-∞ values were respectively 1.6 and 3.3 times greater than the classic cerasome, indicating that despite the presence of a hydrophilic siloxane network, the incorporation of PEG is necessary to reduce the clearance of cerasomes. The comparable PK of PEGylated cerasomes and liposomes, along with the higher physicochemical stability of cerasomes, can be considered an important advantage for the clinical application of cerasomes. Additionally, the easy surface functionalizing ability of cerasomes confers a dual advantage over liposomes. The study findings also showed that the presence of a hydrophilic siloxane network on the surface of cerasomes alone is not enough to make them circulate long.

Hydrophilic nanofibers with aligned topography modulate macrophage-mediated host responses via the NLRP3 inflammasome

Successful biomaterial implantation requires appropriate immune responses. Macrophages are key mediators involved in this process. Currently, exploitation of the intrinsic properties of biomaterials to modulate macrophages and immune responses is appealing. In this study, we prepared hydrophilic nanofibers with an aligned topography by incorporating polyethylene glycol and polycaprolactone using axial electrospinning. We investigated the effect of the nanofibers on macrophage behavior and the underlying mechanisms. With the increase of hydrophilicity of aligned nanofibers, the inflammatory gene expression of macrophages adhering to them was downregulated, and M2 polarization was induced. We further presented clear evidence that the inflammasome NOD-like receptor thermal protein domain associated protein 3 (NLRP3) was the cellular sensor by which macrophages sense the biomaterials, and it acted as a regulator of the macrophage-mediated response to foreign bodies and implant integration. In vivo, we showed that the fibers shaped the implant-related immune microenvironment and ameliorated peritendinous adhesions. In conclusion, our study demonstrated that hydrophilic aligned nanofibers exhibited better biocompatibility and immunological properties.

Improved bleached eucalyptus kraft pulp-based tissue papers incorporating wet-strength resins

Abstract Common tissue paper manufacturing trends aim at partial or total replacement of softwood pulp with hardwood pulp for its production, such as bleached eucalyptus kraft pulp (BEKP), in order to optimize the process and the final product properties such as softness. However, the use of a single type of hardwood fiber results in lower strengths of both wet and dry webs. To maintain necessary strength and desired properties, the incorporation of several additives is often required. In this context, low molecular weight polyethylene glycol (PEG) and different wet strength resins, such as polyamideamine-epichlorohydrin (PAE) and glyoxalated polyacrylamide (GPAM) resins, were combined to achieve an innovated product with improved properties. In particular, wet and dry tensile strength was significantly improved when combining PEG and wet strength resins, especially observed in tissue papers prepared with PAE resin, high-charge cationic agent and bulk applied aqueous PEG solution. Noteworthy that water absorption capacity and softness of tissue paper were not critically affected by PEG incorporation, regardless of application method used (in bulk or by spray).

Green synthesis of polyvinylidene fluoride ultrafiltration membrane with upgraded hydrophilicity

The use of Cyrene™ as an alternative non-toxic solvent to produce a PVDF-based ultrafiltration membrane was investigated in this study. Polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) were used as organic additives to explore its ability to improve membrane hydrophilicity. The additives were introduced into the casting solution via phase inversion with a combined non-solvent induced phase separation (NIPS) and evaporation-induced phase separation (EIPS) technique. The prepared membranes were characterized to examine its morphology, mechanical properties, and filtration performance. The results show that the addition of PEG and PVP has proven able to improve the membrane hydrophilicity with the lowest contact angle of 76.81° achieved from the addition of PEG with concentration 3 wt%. However, the nascent membranes were not adequate enough, in terms of its mechanical properties, to undergo performance tests due to its very brittle nature. The overall results from this study demonstrate a great potential as a proposed method of utilizing Cyrene™ as a choice of green solvent to fabricate PVDF-based ultrafiltration membrane with the incorporation of PEG and PVP as organic additives.

High Affinity and FAP-Targeted Radiotracers: A Potential Design Strategy to Improve the Pharmacokinetics and Tumor Uptake for FAP Inhibitors.

Fibroblast activation protein (FAP) is overexpressed in cancer-associated fibroblasts, making it an attractive target for both imaging and therapy of malignancy. This study presents a range of novel FAP inhibitors derived from amino derivatives of UAMC1110, incorporating polyethylene glycol and bulky groups containing bifunctional DOTA chelators. The compounds labeled with gallium-68 were developed and characterized to study biodistribution properties and tumor-targeting performance in nude mice bearing U87MG tumor xenografts. Several tracers of interest were screened due to the advantages in imaging and tumor-specific uptake. Positron emission tomography scans revealed that polyethylene glycol-modified 68Ga-3-3 had a rapid penetration within the neoplastic tissue and excellent tumor-to-background contrast. In a comparative biodistribution study, naphthalene-modified 68Ga-6-3 exhibited more significant tumor uptake (∼50% ID/g, 1 h p.i.) than 68Ga-3-3 and 10-fold higher than 68Ga-FAPI-04 under the same conditions. Remarkably, 68Ga-8-1, combining the two structural design strategies, obtains superior imaging performance.

Preparation and Characterization of Novel Membrane from Waste Polyethylene terephthalate and Bio-based Polymer

A large amount of post-consumer Polyethylene terephthalate (PET) bottle waste could be recycled for downstream products. In this work, used PET bottles were utilized as a raw material to develop environmentally-friendly ultrafiltration membranes by phase inversion technique. Poly(ethylene-2,5-furandicarboxylate) (PEF), prepared from a sustainable bio-based monomer, 2,5-furandicarboxylic acid (FDCA), was blended into rPET matrix to improve the mechanical properties of the membrane. Ethanol was also used as a non-solvent in a coagulation bath and polyethylene glycol (PEG) with a molecular weight of 400 Da was added as a hydrophilic additive. The effects of PEF and PEG incorporation to waste PET-based membranes have been thoroughly studied. The morphology of obtained membrane was investigated using Scanning Electron Microscopy (SEM). The membrane’s permeation and resistance were tested using a pressure-driven dead-end membrane module. The result revealed that adding PEF increased the roughness of the membrane surface, which lowered the flux recovery ratio and rejection performance. However, the filtration performance and the membrane resistance could be improved by adjusting the content of the PEG additive.

Shape-stabilized phase change material for thermal energy storage: Sr+2 doped BaCO3 matrix incorporating polyethylene glycol

An Sr2+-doped BaCO3 matrix incorporating polyethylene glycol (PEG-6000) was developed using a simple impregnation process to build a shape-stabilized functional phase transition composite for application in thermal energy storage systems. A direct hydrothermal process was used to prepare a unique anhydrous rhombohedral BaCO3. The developed rhombohedral material, characterized following a hydrothermal reaction in the presence of 5 mol% Sr2+, was used to prepare extremely tiny porous particles (5 % SrBaCO3). The 5 % SrBaCO3 powder was hydrothermally produced and utilized to encapsulate PEG to create a phase change material (PCM) that prevents leakage of PEG during phase change. The shape-stabilized composite PCM (ss-PCM) that was prepared with nano- and micro-sized porous SrO powder and containing pure BaCO3 exhibited consistent and superior performance throughout a significant number of heat cycles. DSC results indicated that the melting temperature of the PEG/5BaCO3 is 60.17 °C, and the latent heat is 148.8 J/g. The R% (Impregnation ratio) and Eeff% (Efficient energy per unit mass of PEG) values of 5 % SrBaCO3 were more than those of 10 % SrBaCO3 and 15 % SrBaCO3, probably due to the presence of micro- and macro-pores and high pore volume. Additionally, it was clear from the XRF, EDX, and XPS data that Ba2+ segregation in 5 % SrBaCO3 was considerably less than that in 10 % SrBaCO3 and 15 % SrBaCO3. Compared to the long-established ss-PCMs, the developed composites exhibited much greater thermal enthalpy, higher thermal conductivity, and lesser super cooling. The presence of OH−1 on the surface of the PCM contributed to a reduction in the super cooling. Furthermore, the supporting materials improved the thermal conductivity of the PEG, overcoming the organic PCM's poor thermal conductivity. As pure PEG is infused in 5 % SrBaCO3, its super cooling effect is diminished by 15.5 %. Overall, the PCM with 5 % SrBaCO3/PEG preserves its capacity to store and release energy without a substantial modification its properties after multiple thermal heating and cooling cycles.

Shape-stabilized phase change composites supported by biomass loofah sponge-derived microtubular carbon scaffold toward thermal energy storage and electric-to-thermal conversion

Integrating conductive carbon supports and organic phase change materials (PCMs) facilitates the development of thermal energy storage (TES) and conversion systems. Herein, we explore a novel phase change composite (PCC) based upon biomass-derived carbon scaffold incorporating polyethylene glycol (PEG) as a heat storage unit, which demonstrated a combination of good shape-stabilization, high thermal energy storage, and efficient electric-to-thermal conversion property. The carbon scaffold with a hollow microtubular structure was made from biomass loofah sponge (LS) through high-temperature carbonization in nitrogen. Compared with natural LS, the derived carbon scaffold exhibited favorable structural characteristics including a large specific surface area of 668.75 m2/g and a prominent micropore area of 303.37 m2/g, which could not only prevent PEG from leakage but also provide thermally and electrically conductive pathways in the PCM substance. The fabricated PCC displayed high thermal energy storage density (up to 137.6 J/g), outstanding electric-to-thermal conversion, enhanced thermal resistance, and robust temperature regulation properties. It provides an insightful strategy for fabrication and utilization of biomass-derived carbon scaffold based shape-stabilized PCCs in solar thermal energy storage, thermal management and thermoregulated textiles, and infrared stealth of important military targets, etc.

Application of Ethyl Cellulose and Ethyl Cellulose + Polyethylene Glycol for the Development of Polymer-Based Formulations using Spray-Drying Technology for Retinoic Acid Encapsulation.

Ethyl cellulose (EC)-based microparticles, with and without the incorporation of polyethylene glycol (PEG) as a second encapsulating agent, were prepared using the spray-drying process for the encapsulation of retinoic acid (RA). The production of a suitable controlled delivery system for this retinoid will promote its antitumor efficiency against acute promyelocytic leukemia (APL) due to the possibility of increasing the bioavailability of RA. Product yield ranged from 12 to 28% in all the microparticle formulations, including unloaded microparticles and RA-loaded microparticles. Microparticles with a mean diameter between 0.090 ± 0.002 and 0.54 ± 0.02 µm (number size distribution) and with an irregular form and rough surface were obtained. Furthermore, regarding RA-loaded microparticles, both polymer-based formulations exhibited an encapsulation efficiency of around 100%. A rapid and complete RA release was reached in 40 min from EC− and EC + PEG-based microparticles.

Highly Stretchable and Elastic Polymer Electrolytes with High Ionic Conductivity and Li‐Ion Transference Number for High‐Rate Lithium Batteries

Comprehensive SummaryThe ever‐growing demand for wearable electronics drives the development of stretchable lithium‐ion batteries (LIBs) with fast charging capability, in which stretchable polymer electrolytes (PEs) with high ionic conductivity and lithium‐ion transference numbers () are highly desirable. Herein, we report a highly stretchable and elastic PE with high ionic conductivity and , which is applicable in high‐rate and stretchable LIBs. The PE was fabricated by incorporating polyethylene glycol (PEG) and lithium salts into polyurethane networks, wherein α‐cyclodextrin (α‐CD) acts as the cross‐linker. The PEG chains are cross‐linked by covalent and noncovalent bonds, and some PEG chains enter into the cavity of α‐CD to form PEG/α‐CD inclusions. These structural features effectively suppress crystallization of the PEG chains, hinder movement of the counterions of Li+, and endow PE with satisfactory mechanical robustness. The PE with a tensile strength (0.61 MPa) exhibits a large strain at break (840%) and excellent elasticity, possessing a high ionic conductivity (5.0 × 10–4 S·cm–1) and a high (0.52). The Li‖LiFePO4 battery assembled with the PE delivers a high capacity of 75 mAh·g–1 even at the high rate of 16 C. The battery can be stably cycled for 300 and 200 cycles at 1 C and 4 C, respectively.

Polyethylene glycol functionalized reduced graphene oxide coupled with zinc oxide composite adsorbent for removal of phenolic wastewater

The development of agricultural activities and industrialization recently has various adverse impacts on living organisms. The ever-increasing problem of organic pollution has been an environmental concern to the community. Among these, phenolic pollutants like 2,4–dichlorophenol (2,4–DCP), phenol, 2–chlorophenol (2–CP), and bisphenol–A (BPA) are priority toxic pollutants that are continuously released into environment from many industries. In this work, a biocompatible zinc oxide incorporated polyethylene glycol functionalized reduced graphene oxide composite (RGO-PEG-ZnO) was synthesized and explored for the adsorptive removal of toxic phenolic pollutants from water. The optimized adsorption parameters were solution pH 7, adsorption time 60 min, temperature 25 °C, and dosage 0.25 g/L. The isotherms were well fitted by the Langmuir model for BPA and phenol, whereas for 2–CP, and 2,4–DCP, Freundlich was the best-fitted model, and the maximum uptake of BPA, phenol, 2–CP, and 2,4–DCP were 485.756, 511.248, 531.804, 570.641 mg/g, respectively. The kinetic data for all the phenolic pollutants follow the pseudo-second-order model. The thermodynamic analysis shows that Gibb's free energy (ΔGo) values for all the pollutants were negative, confirming that the process was spontaneous. The positive values of change in enthalpy (ΔHo) 28.261, 37.205, 46.182, and 61.682 kJ/mol for BPA, phenol, 2–CP, and 2,4–DCP, respectively, confirm that the above adsorption process was endothermic. The composite can be used for up to five cycles with a small reduction in the removal percentage. Adsorption performance of the synthesized composite for synthetic industrial effluents shows that up to 86.54% removal occurred in 45 min adsorption time. Based on the remarkably rapid adsorption and high adsorption capacity, RGO-PEG-ZnO composite can be considered an efficient adsorbent for treating phenolic pollutants from wastewater.

Multi-Resin Masked Stereolithography (MSLA) 3D Printing for Rapid and Inexpensive Prototyping of Microfluidic Chips with Integrated Functional Components.

Stereolithography based 3D printing of microfluidics for prototyping has gained a lot of attention due to several advantages such as fast production, cost-effectiveness, and versatility over traditional photolithography-based microfabrication techniques. However, existing consumer focused SLA 3D printers struggle to fabricate functional microfluidic devices due to several challenges associated with micron-scale 3D printing. Here, we explore the origins and mechanism of the associated failure modes followed by presenting guidelines to overcome these challenges. The prescribed method works completely with existing consumer class inexpensive SLA printers without any modifications to reliably print PDMS cast microfluidic channels with channel sizes as low as ~75 μm and embedded channels with channel sizes as low ~200 μm. We developed a custom multi-resin formulation by incorporating Polyethylene glycol diacrylate (PEGDA) and Ethylene glycol polyether acrylate (EGPEA) as the monomer units to achieve micron sized printed features with tunable mechanical and optical properties. By incorporating multiple resins with different mechanical properties, we were able to achieve spatial control over the stiffness of the cured resin enabling us to incorporate both flexible and rigid components within a single 3D printed microfluidic chip. We demonstrate the utility of this technique by 3D printing an integrated pressure-actuated pneumatic valve (with flexible cured resin) in an otherwise rigid and clear microfluidic device that can be fabricated in a one-step process from a single CAD file. We also demonstrate the utility of this technique by integrating a fully functional finger-actuated microfluidic pump. The versatility and accessibility of the demonstrated fabrication method have the potential to reduce our reliance on expensive and time-consuming photolithographic techniques for microfluidic chip fabrication and thus drastically lowering our barrier to entry in microfluidics research.

Thermal, mechanical and morphological properties of plasticized polyurethane binders based on PEG and HTPB blends

Improving the properties of hydroxyl-terminated polybutadiene (HTPB) has always been one of the important topics for researchers in the propellant field. In this research work, a prepolymer from blend of HTPB and polyethylene glycol (PEG) is prepared with isophorone diisocyanate (IPDI). This prepolymer is mixed with glycerol for the synthesis of polyurethane (PU) elastomer. The compatibility of n-butyl nitroxyethylnitramine (n-BuNENA) as an energetic plasticizer with a non-energetic PU matrix was investigated. The properties of HTPB-PEG blend elastomer prepared with n-BuNENA plasticizer were compared with elastomers made by HTPB. The results of SEM analysis showed that incorporation of PEG improved the compatibility of plasticizer with PU matrices. DSC, FTIR spectroscopy and tensile analysis revealed that the phase separation degree and crystallinity in PEG-based PU were much higher than HTPB elastomer. It was determined by TGA results that the n-BuNENA plasticizer reduced the thermal stability of PU. Mechanical studies also indicated that the incorporation of PEG increases the modulus and tensile strength while the addition of plasticizer decreases the modulus and enhances the tensile strength and elongation.

Fabrication of electrospun nanofibers with moisture-triggered carvacrol release in fresh produce packaging.

In this study, by incorporating polyethylene glycol (PEG) into the polylactic acid (PLA) nanofibers, a moisture-controlled system was developed in the release of carvacrol to the food package headspaces. With the use of electrospinning technology, an optimized solution (80:20 [PLA:PEG] polymer mixture incorporated with a carvacrol content of 20% [w/w polymer]) generated nanofibers with excellent encapsulation efficiency, loading capacity, and controlled release of carvacrol at different humidity levels. Carvacrol was prevented from release when the fibers were kept in dry states. When placed in food packaging with high humidity levels, the nanofibers manifested high and continuous release of carvacrol into the headspace. The shelf life of strawberries determined by visual inspection was extended for 2 extra days when packaged with the optimized nanofibers and had a significantly lower yeasts and mold counts (4.28±0.34 log CFU/g) compared to strawberries packaged without nanofibers (5.22±0.47 log CFU/g) 3 days after applying the nanofibers (p<0.05). PRACTICAL APPLICATION: The nanofibers with PEG content as developed in this study represent a step forward in practical application of the electrospinning technology to enhance food quality in food preservation.