Miniemulsion Polymerization Research Articles

Graphene functionalized nanoencapsulated composite phase change material based nanofluid for battery cooling: An experimental investigation

The graphene-nano encapsulated composite phase change material (GnePCM) based nanofluid holds great potential as a coolant for batteries in electric vehicles. The current work focuses on the synthesis and study of the cooling performance of GnePCM-based nanofluid. Few layered graphene (FLG) was synthesized via the liquid phase exfoliation method. Mini-emulsion polymerization was adopted to encapsulate composite PCM (octadecane: paraffin wax) within polystyrene shell and distribute these nanoballs across the graphene flakes of FLG to obtain GnePCM. Differential Scanning Calorimetry (DSC) was used to optimize the composition of composite PCM based on the melting range and latent heat. GnePCM was characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), DSC, Fourier Transform Infrared (FTIR) spectroscopy, and Raman Spectroscopy. Nanofluid was made by mixing GnePCM slurry with the base fluid (ethylene glycol − water mixture) and its thermo-physical properties were estimated. The analysis of thermal conductivity and specific heat capacity showed a 14.7 % and 56 % increase for the nanofluid compared to the base fluid. The optimal concentration of nanofluid for maximum stability was 10 % v/v based on zeta potential measurements. The heat transfer studies and pressure drop studies were conducted on a set of 10 cylindrical heaters, mimicking a 18,650 battery cell pack. The nanofluid could potentially achieve a maximum reduction of 5 °C in average surface temperatures of the cells as compared to the base fluid. The enhanced cooling efficiency of nanofluid could be related to the increased thermal conductivity and heat capacity of GnePCM, as well as the absorption of latent heat during its melting process. Enhancement in heat transfer parameters was found to be more prominent at lower flow rates for the nanofluids. The results reveal that the flow rate and power input play a significant role in the cooling performance of the nanofluid. Due to the increased viscosity of the nanofluid, a slight increase in the pressure drop and pumping power was observed at higher flow rates, as compared to base fluid.

Scalable Synthesis of Degradable Copolymers Containing α-Lipoic Acid via Miniemulsion Polymerization.

A robust method is described to synthesize degradable copolymers under aqueous miniemulsion conditions using α-lipoic acid as a cheap and scalable building block. Simple formulations of α-lipoic acid (up to 10 mol %), n-butyl acrylate, a surfactant, and a costabilizer generate stable micelles in water with particle sizes <200 nm. The ready availability of these starting materials facilitated performing polymerization reactions at large scales (4 L), yielding 600 g of poly(n-butyl acrylate-stat-α-lipoic acid) latexes that degrade under reducing conditions (250 kg mol-1 → 20 kg mol-1). Substitution of α-lipoic acid with ethyl lipoate further improves the solubility of dithiolane derivatives in n-butyl acrylate, resulting in copolymers that degrade to even lower molecular weights after polymerization and reduction. In summary, this convenient and scalable strategy provides access to large quantities of degradable copolymers and particles using cheap and commercially available starting materials.

Fabrication and evaluation of eicosane/poly(styrene-co-butylacrylate) microencapsulated phase change materials through ultrasonicated mini-emulsion technique

This study reports the synthesis and characterization of Microencapsulated Phase Change Materials for the pertinence of latent heat storage. Eicosane/ Poly(Styrene-co-Butylacrylate) [ESE/Poly(Sty-co-BA)] microcapsules were synthesized by encapsulating n-Eicosane (n-ESE) with a shell made of Poly(Styrene-co-Butylacrylate) [Poly(Sty-co-BA)] via employing ultrasonic-assistant mini-emulsion polymerization technique. The properties of the synthesized ESE/Poly(Sty-co-BA) microcapsules were analyzed by Differential scanning calorimetry (DSC),Thermogravimetric analysis (TGA), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR)spectroscopy. DSC results indicated that ESE/Poly(Sty-co-BA) exhibited a melting and crystallizing temperature of 35.72 and 32.27 °C, and latent heat of 220.53 and 218.57 J/g, respectively. The ESE/Poly(Sty-co-BA) microcapsules prepared in this work unveiled an effective encapsulation ratio (91.93 %), encapsulation efficiency (91.59 %) and displayed excellent thermal storage capacity (99.63 %). Various models such as Kissinger’s, Augis and Bennett’s approximation, Mahadevan and Arvami theory were employed to determine the effective activation energy value alongside the crystal growth of n-ESE and ESE/Poly(Sty-co-BA). TGA analysis revealed that ESE/Poly(Sty-co-BA) demonstrated three step degradation and exhibited good thermal stability. The findings of the work manifested a novel technique for producing the phase transition materials for TES that can be applied to a wide range of instances, including smart textiles, thermo-sensitized functional coatings, passive space cooling or heating.

Monomer Transport via Collision in Emulsion Polymerization

AbstractOne of the questions still remaining regarding emulsion polymerization is the issue of mass transfer versus reaction limitation since, by its nature, emulsion polymerization requires monomer transport across an aqueous phase. This question is brought into focus lately by the growing use of miniemulsion polymerization in which the monomer transport step is much less important. This paper will explore the possible rate of monomer transport via collision and ratio this to the maximum rate of polymerization using the Damkohler analysis formality. Results indicate that systems relying on monomer transport by collision will be almost universally monomer‐transport‐limited, thus exhibiting lower‐than‐expected rates of polymerizations.

UV Filter NanoCapsule with Broad‐Spectrum UV Protection

AbstractIn this study, nanocapsules encapsulating avobenzone (AVB) compounded with isooctyl p‐dimethylaminobenzoate (OD‐PABA) were prepared via miniemulsion polymerization using methyl methacrylate (MMA) as the monomer, ethylene glycol dimethacrylate (EGDMA) as the cross‐linker, and poly(styrene‐co‐methacrylic acid) (P(St‐co‐MAA)) as the polymeric emulsifier. When a solid ultraviolet radiation A (UVA) filter, AVB, was encapsulated in nanocapsules (A‐UVNCs), the encapsulation and loading rates were 67.6% and 9.7%, respectively. When a liquid ultraviolet radiation B (UVB) filter, OD‐PABA, was combined with AVB, the encapsulation and loading rates of the nanocapsules (A/O‐UVNCs) of AVB and OD‐PABA increased to 90.0% and 15.6%, respectively, and 71.5% and 14.0%, respectively. The A/O‐UVNCs realized broad‐spectrum ultraviolet (UV) protection with an SPF value of 46.3. The A/O‐UVNCs have raspberry‐like nanostructures. These submicron particles can scatter and reflect a portion of the UV radiation and synergistically enhance UV protection. After exposure to simulated sunlight for four hours, the UVAPF of a sunscreen containing A‐UVNCs or A/O‐UVNCs decreased to a smaller extent than that of the sunscreen containing free AVB. Cell toxicity experiments showed that the cell viability of A‐UVNCs and A/O‐UVNCs was 85.9% and 83.0%, respectively. Therefore, UVNCs not only enhance UV protection but also improve photostability and safety.

Behind the scenes of green chemistry: Glories and shadows of atom transfer radical polymerization environmental impact (E-factor)

The paper presents the evaluation of environmental impact (E-factor) as green chemistry metric, calculated for polymer synthesis via one of the most useful tools of macromolecular chemistry, which is atom transfer radical polymerization (ATRP), belonging to the reversible deactivation radical polymerization (RDRP) techniques. For the first time, experimentally determined polymerization yields were included in the calculation, by analyzing the polymer synthesis process using various organic solvents, different methods of regenerating the catalytic complex (meaning ATRP approach), or using the miniemulsion system as eco-friendly reaction medium and presenting the possibility of effective solvent recovery and reuse. The majority of the values of E-factor were below 16, falling within the scope intended for fine chemicals (5–50). The significant and innovative part of the presented research involves verifying the feasibility of using higher concentrations of the dispersed phase in the case of miniemulsion polymerization (increased to as much as 100 % vs. aqueous phase from a typical 20 %), while the use of recycled water allowed a 3-fold reduction in E-factor value. Polymerization in a miniemulsion environment is also attractive due to its low cost, considering the price of distilled water, which is over 580-fold lower than that of DMSO – a typical organic solvent. These observations allow for the reduction of environmental impact and process cost. Importantly, the observed trends in E-factor changes allowed for the identification of ATRP development directions in line with green chemistry and the circular economy.

Surfactant-Free Preparation of Conjugated Polymer Nanoparticles in Aqueous Dispersions Using Sulfate Functionalized Fluorene Monomers.

Conjugated polymer nanoparticles (CPNs) can be synthesized by a Suzuki-Miyaura cross-coupling miniemulsion polymerization to give stable dispersions with a high concentration of uniform nanoparticles. However, large amounts of added surfactants are required to stabilize the miniemulsion and prevent the aggregation of the nanoparticles. Removal of the excess surfactant is challenging, and residual surfactant in thin films deposited from these dispersions can reduce the performance of optoelectronic devices. We report a novel approach to prepare stable dispersions with no added surfactant using a fluorene monomer, 2,7-dibromo-9,9-bis(undecanesulfate)-9H-fluorene, with alkyl side chains terminated by negatively charged sulfate groups. This functionality mimics the structure of one of the most commonly used surfactants, sodium dodecyl sulfate (SDS). This charged monomer effectively stabilizes the miniemulsion through electrostatic repulsion without the use of any additional surfactant in molar ratios ranging from 2.0 to 20.0 mol % of total monomer content for the preparation of poly(9,9-dioctylfluorene) (PFO) and poly(9,9-dioctylfluorene-alt-bithiophene) (PF8T2). Incorporation of 5.0 mol % of the amphiphilic monomer gave stable dispersions with a surface potential below -40 mV and, and polymers with molar mass (Mn) above 10 kg mol-1. This method should be generally applicable to the preparation of dispersions of polyfluorenes for application in organic electronic and optoelectronic devices without the requirement for time-consuming processes to remove residual surfactant.

Proline-Functionalized Magnetic Nanoparticles as Highly Performing Asymmetric Catalysts.

Amino acids have a crucial role in the field of asymmetric organocatalysis for the production of chiral compounds with high added value and specific biological activity. In particular, proline offers high activity and stereoselectivity for catalyzing aldol reactions in organic solvents. However, proline-based catalysts often lack water-solubility, accessibility, catalytic performance, or recovery in aqueous media. This work reports the design of proline-functionalized poly(methyl methacrylate) (PMMA) nanoparticles with a magnetic core that offer high availability of chiral units in water and high recyclability. A proline-based copolymerizable surfactant is designed and integrated onto the surface of PMMA nanoparticles through a miniemulsion polymerization process without using additional surfactants. The miniemulsion technique allows the incorporation of magnetite to the system to create a magnetically separable catalyst. The chiral nanocatalyst presents a high diastereoselective catalytic activity for the intermolecular aldol reaction between p-nitrobenzaldehyde and cyclohexanone in water.

Monomer Transport by Collisions in (Mini) Emulsion Polymerization, a Personal Perspective

AbstractTransport of monomer from droplets to growing latex particles in emulsion polymerization in general is assumed to proceed via diffusion through the aqueous phase. Especially in miniemulsion polymerizations the direct transfer of very hydrophobic species from droplet to droplet is assumed to also proceed via collisions. Amongst the hydrophobic species where this is shown to play a role are monomers, initiators, inhibitors and (catalytic) chain transfer agents. It is well known that the reactor geometry and the stirring speed can have a profound effect on emulsion polymerizations. The 1972 paper of Nomura on the effect of stirring on emulsion polymerization is cited more than 100 times and until today keeps scientists intrigued. Diffusion limitations of monomer going from the droplet into the aqueous phase can occur for very hydrophobic monomers. The alternative route of transport via collisions is often not considered. In this perspective, paper will discuss the evidence for collision based transfer in miniemulsion polymerization and also consider whether collision based monomer transport can play a role in regular emulsion polymerizations.

One-step nanoencapsulation of essential oils and their application in hybrid coatings: A sustainable long-lasting treatment of stone materials against biodeterioration

In this study, two essential oils (EOs) with preventive proved biocidal efficacy, namely oregano and eugenol, are encapsulated in silica nanocontainer, then dispersed in multifunctional, hybrid and nanocomposite coating. The aim of this work is to reduce toxicity of restoration materials, to avoid the chemicals dispersion in the environment and to extent stone protection treatments, preventing biofouling.Composite silica nanocapsules, containing separately the two EOs, are prepared via one-step synthesis, based on oil-in-water miniemulsion polymerisation processes, and fully characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 physisorption (BET/BJH). Micro-Raman spectroscopy (RS) and thermal analysis (TG/DSC).In a second step, nanocomposite coatings, based on a flexible tetraethyl orthosilicate (TEOS) matrix, are synthesised dispersing TiO2 nanoparticles and the two silica nanocapsules incorporating EOs. The coatings were applied on three different lithotypes samples of historical importance: brick, piperine and mortar. The effectiveness and compatibility of the coating formulation with the different stone substrates were assessed through a multi-analytical standard protocol.The silica nanocapsules, show monodispersed spherical shape with size ∼110 nm, a core-shell structure, a BET surface area of 600–700 m2/g and high loading capacity.The results on coatings characterisation show a crack-free and transparent structure. Moreover, the tests on applied coatings reveal the high hydrophobicity of the treated stone samples (static contact angle in the range ∼ 130–140° and reduction of liquid water capillary absorption 97–99 %) and unaltered permeability to water vapour (density of water vapour flow rate in the range 150–200 g/m2·d), demonstrating the suitability of the nanocomposite hybrid coatings for the application in stone protection against biodeterioration.

Direct Acrylation of Soybean Oil and the Influence of the Acrylation Degree on Waterborne Acrylic Systems.

The direct acrylation of soybean oil was investigated by the activation of soybean oil's (SO's) internal fatty unsaturation with acidic catalysts. The effect of the catalyst and the reactant ratio with respect to the unsaturation and reaction time on the direct acrylation process were explored. ASO (acrylated soybean oil) with acrylation degrees (the number of acrylate molecules introduced in a triglyceride molecule) between 1.6 and 2.55 were obtained. The effect of the ASO acrylation degree on copolymerization processes was investigated. The resulting monomers were successfully copolymerized with meth(acrylate) monomers by the miniemulsion polymerization process, favoring the droplet nucleation mechanism and showing conversions higher than 97%. The acrylic-ASO copolymers presented lower Tg and higher hydrophobicity and oleophobicity than the acrylic copolymer.

A second law analysis on flow of a PCM based nanofluid in a shell-and-tube heat exchanger: An experimental study for sustainable energy

In the foreseeable future, heat exchangers will continue to play an important role in environmental management and have numerous applications, their geometry has been the subject of interest for many researchers. The main goal of this research is to improve the heat exchangers' thermal performance and exergetic efficiency using new type of nanofluid. In this concept, the effect of nanoencapsulated phase change material (NEPCM) addition to water and producing NEPCM nanofluid for heat transfer augmentation in shell and tube heat exchanger (STHE) was investigated, experimentally. Nanocapsules were synthesized by miniemulsion polymerization containing phase change material (PCM) as core and chitosan (GO/CS) as shell material. After synthesis of nanocapsules, nanofluids with different concentration of NEPCM have been prepared and the stability and thermophysical properties of the nanofluids were characterized. In the subsequent stage, thermal and exergy efficiencies test was conducted on STHE using response surface method. The experiments were performed at different conditions; NPCM concentration (φ), inlet temperature (Tin) and Re number to optimse exergy efficiency. The optimum level of the φ, Tin and Re inlet for maximum ɛ (73 %) were found to be 10.55 %, 78.35 °C and 10365, respectively. The experimental results demonstrated that proposed nanofluid could enhance exergy efficiency for thermal system. It appears that a combination of NEPCM nanofluids gives a better cooling rate in the heat exchangers and could be a promising alternative along with other cooling techniques.

Leaching-Free durable antibacterial composite films constructed via delicate balance between potent contact sterilization and low adhesion

Durable antibacterial surfaces are often required high bactericidal ability and low bacterial adhesion property, but the potent bactericidal surfaces, especially based on the contact bactericidal mechanism, are often paradoxically intended to attract bacteria to adhere. In this work, a delicate balance between the potent contact bactericidal action and low bacterial adhesion was successfully achieved in quaternized fluoropolymer/SiO2 composite films (QFP/SiO2 CFs) through judicious selection of a common fluorinated monomer, a common quaternary ammonium monomer, and a common inert inorganic nanoparticle, to acquire suitable surface energy and chain mobility to ensure low bacterial adhesion, as well as to allow appropriate surface-exposed quaternary ammonium units to synergistically enhance the contact bactericidal action with the specific fluorinated side chains. The QFP/SiO2 CFs were conveniently fabricated through miniemulsion polymerization and followed squeegeeing technique. The QFP/SiO2 CF with an optimized composition exhibited extremely low initial adhesion of bacteria, potent contact bactericidal action, superior long-term antibacterial performance, easy sonication-assistant regeneration for multiple usage, and low cytotoxicity with non-leachable attribute. This work may guide the design and efficient fabrication of leaching-free durable antibacterial surfaces for biological applications, as well as provide an effective strategy to balance contact bactericidal action and low bacteria adhesion for durable antibacterial performance.

PH-induced fluorescent active sodium alginate-based ionically conjugated and REDOX responsive multi-functional microgels for the anticancer drug delivery

A sodium alginate (Alg) based REDOX (reduction and oxidation)-responsive and fluorescent active microgel was prepared via water in oil (w/o) mini-emulsion polymerization technique. Here, we initially synthesized sodium alginate-based disulfide cross linked microgels and after that those microgels were tagged with rhodamine amine derivative (RhB-NH2) by ionic interaction to get the pH-responsive fluorescent property. Functionalized microgels were characterized using 1H NMR, FTIR, DLS, HRTEM, FESEM, UV–vis, and fluorescence spectroscopy analyses. Presence of the REDOX-responsive disulfide-containing crosslinkers in the microgels enhances the release of doxorubicin (DOX), an anti-cancer drug in the reducing environment of the cancer-cells (simulated). Existence of the rhodamine-amine derivative in the microgels triggers the pH-dependent fluorescence property by showing fluorescence emission at 560–580 nm at pH 5.5 (cancer cell pH). The cytotoxicity of the biopolymer based microgel was assessed over both cancerous HeLa (IC50 100 µg/mL) and non-cancerous MDCK (IC50 200 µg/mL) cells by MTT assay which showed the synthesized microgel is non-toxic whereas DOX-loaded microgels showed significant toxicity. FACS and cell uptake (in vitro) analyses were conducted to understand the cell apoptosis cycle and behavior of the cancer cells in presence of the DOX-loaded microgels. This pH-responsive fluorescent active alginate-based biomaterial could be a promising material for the anti-cancer drug delivery and other medical fields.

Organofluorosilicon Modified Polyacrylate with the Unidirectional Migration Promotion of Disperse Dyes toward Polyester Fabric for Wash-Free Digital Inkjet Dyeing.

The printing and dyeing industry is currently accelerating toward a direction of high efficiency, energy conservation, environmental protection, and integration with digitalization. Disperse dye wash-free digital inkjet dyeing is a revolutionary breakthrough for cleaning and coloring polyester fabric. Based on the solubility parameters and the hot-melt dyeing characteristics of disperse dyes, soft, hard, and functional monomers of acrylate were used as the main body. Moreover, single-vinyl fluorinated polysiloxane and divinyl polysiloxane with low solubility parameters were used as modified monomers. A modified polyacrylate (PFSMA) adhesive containing silicon in the main chain and fluorine silicon in the side chain was prepared via miniemulsion polymerization. Using disperse digital inkjet dyeing of polyester fabric without washing can realize energy saving, emission reduction, and carbon reduction. Results showed that the optimum preparation conditions of PFSMA were as follows: DVFS molecular weight of 957 g/mol and DVFS content of 2.5 wt %. Compared with that of polyacrylate (PA), the glass-transition temperature of PFSMA film decreased, and its water resistance, toughness, and adhesion enhanced. When the PFSMA content in the wash-free disperse red ink was 8 wt %, the color yields of the front and back of the PFSMA jet-dyed polyester fabric were 18.86 and 13.28, respectively. Moreover, the color yield of the front of PFSMA jet-dyed polyester fabric was 39.9% higher than that of the pure liquid disperse red jet-dyed fabric. The simulated fixation rate was 87.9%, approximately 2.9 times higher than that of the PA wash-free jet-dyed fabric. The color fastness to dry rubbing reached level 4 and the color fastness to wet rubbing reached level 3-4, which was one level higher than that of pure liquid disperse red jet-dyed fabrics. The color fastness to soaping reached grade 5 and the color fastness to heat compression reached grades 4-5 and above. The fabric was a little firmer but smoother. The color properties, color fastness, and hand feeling of the PFSMA wash-free jet-dyed polyester fabric exceeded the levels of commercially available adhesives.

Interfacial distribution of PMMA-grafted MWCNTs in immiscible blends for improved electrical conductivity

Engineering blend structure with interfacial distribution of nanoparticles is a cost-effective strategy for achieving materials with extraordinary performances. Herein, poly (methyl methacrylate) (PMMA) homopolymer was sparsely grafted onto the surface of hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) by miniemulsion polymerization and such modified MWCNTs-g-PMMA were introduced into immiscible engineering blend of polycarbonate (PC) and polyvinylidene fluoride (PVDF) to prepare conductive polymer composites (CPCs). With the help of the miscibility of PMMA with PC and PVDF, MWCNTs-g-PMMA were selectively located at the interface of co-continuous PC/PVDF blend, while MWCNTs-OH were distributed in the PC phase. The interfacial distribution and aggregation of MWCNTs-g-PMMA endowed the ternary nanocomposite with long-term stable excellent electrical conductivity and ultralow percolation threshold of 0.002 vol%.

Salt-responsive polyamide thin-film nanocomposite membrane based on zwitterionic polymeric nanoparticles for high-efficient dye desalination

To simultaneously improve the water permeability, selectivity, and antifouling properties of polyamide nanofiltration (NF) membranes in textile wastewater treatment, we fabricated a salt-responsive thin-film nanocomposite (TFN) membrane with the incorporation of zwitterionic polymeric nanoparticles (ZNPs) into polyamide selective layer. Herein, the ZNPs were synthesized via an inverse miniemulsion polymerization with zwitterionic monomer, amino monomer, and cross-linker reagent. The salt-responsive property of ZNPs rendered their resultant membranes TFN-ZNPs with adjustable microstructure and separation performance via varying the sodium chloride (NaCl) concentration in water. The water permeance of TFN-ZNPs was enhanced to be 1.7 times that of its pure water permeance with the 10 g L−1 NaCl solution, and the salt-responsive behavior was reversible. Moreover, this salt-responsive property endowed the membrane with outstanding separation performance for the salt/dye or dye/dye mixtures. The selectivity of TFN-ZNPs to NaCl/congo red and methyl orange/neutral blue was enhanced to ∼104 and ∼127, respectively. The TFN-ZNPs with salt-responsive property also exhibited an improved antifouling performance, i.e., the flux recovery ratio was enhanced from 85.6 % to 96.5 % by washing with NaCl solution instead of deionized water. Thus, this work provided a paradigm shift in the fabrication of salt-responsive TFN membranes for the highly efficient separation of organic molecules and inorganic salts and wastewater treatment.

Preparation and thermal properties of latent functional thermal fluid based on size-controllable phase change nanocapsules

Size-controllable 1-octadecanol@polystyrene phase change nanocapsules (NEPCMs) were prepared using the miniemulsion polymerization and dispersed in deionized water containing multi-walled carbon nanotubes to prepare a latent functional thermal fluid (LFTF). The results demonstrate that the NEPCMs exhibit a typical core-shell structure. The average particle size (55.28–143.8 nm) of the NEPCMs can be regulated by controlling the content of compound emulsifiers. The optimal phase change enthalpy has an excellent heat storage capacity of about 222.7 J/g, the encapsulation efficiency is up to 80.63 %, and the average particle size is about 88.3 nm. The heating/cooling cycles results show that NEPCMs have excellent cycle stability. LFTF containing 10 wt% NEPCMs was considered the optimal choice for its excellent photothermal conversion efficiency (up to 64.91 %), excellent dispersion stability (zeta potential 39.17 mV) and thermal storage capacity (peak specific heat capacity 5.72 J g−1 K−1). Under the influence of solar radiation, the temperature rise curve of LFTF exhibited a rapid initial warming rate followed by a plateau period of approximately 76 min upon reaching the melting point of the NEPCMs, whose photothermal conversion efficiency is roughly 2.18 times that of water. The experimental findings demonstrate the potential application of LFTF based on NEPCMs in the solar thermal industry.

L-proline determination by molecularly imprinted nanoparticles: A potential nanoscale tool for the diagnosis of metabolic disorders

Detecting and quantifying amino acids is vital in biochemical analyses, especially for diagnosing metabolic disorders. L-proline, among these amino acids, holds significant relevance for various metabolic disorders in living organisms, particularly in humans. hyperprolinemia arises when ineffective breakdown of L-proline occurs due to enzyme deficiencies, leading to its accumulation in the body and underscoring the need for precise monitoring. To address this challenge, molecular imprinting offers a reliable single-step technique for detecting target molecules like proteins, peptides, amino acids, or ions with high selectivity. Moreover, nanoparticles, with significant surface area-to-volume ratios, enable high-level mass transfer and binding kinetics, making them ideal for nano-scale sensitive applications. In this study, 2-hydroxyethyl methacrylate-based molecularly imprinted nanoparticles were synthesized via mini-emulsion polymerization, combining the advantages of molecular imprinting technique and nanoparticles for the specific recognition of L-proline, and were well-characterized by Scanning Electron Microscopy, zeta-sizer particle size analysis, and Fourier Transform Infrared Spectroscopy. Based on zeta-sizer analysis, the estimated diameters of L-proline-imprinted and non-imprinted nanoparticles (Pro-MIPs and NIPs) were determined to be approximately 27.51 nm and 20.66 nm, respectively. The adsorption of L-proline onto nanoparticles from aqueous solutions was investigated in a batch system, and the maximum L-proline adsorption capacity was determined to be 26.58 mg/g for Pro-MIPs and 4.65 mg/g for and NIPs. The selectivity of Pro-MIPs was assessed using Liquid Chromatography-Tandem Mass Spectrometry, even in human serum and in the presence of competing molecules (L-histidine and L-phenylalanine). Additionally, Pro-MIPs maintained their adsorption capacity through up to 10 adsorption-desorption cycles without significant decrease.

Encapsulation of organic ultraviolet photoprotective actives into poly(methyl methacrylate) nanoparticles for sunscreen formulations

AbstractSkin cancer is the most common of all cancers worldwide. This way, it is mandatory to adopt an adequate sun protection routine, including sunscreen lotions. However, despite the proven effectiveness of numerous chemical filters, many of them are also known for their allergenic and carcinogenic potential effects, which can be mitigated by exploring some encapsulation routes. Thus, the present work evaluates the influence of seven distinct ultraviolet (UV) organic filters on the final particle size and molecular weight distributions of poly(methyl methacrylate) (PMMA) beads. Moreover, the sun protection factors (SPF) of the loaded nanoparticles are also evaluated when used for preparation of sunscreen formulations. The UV filters did not affect the course of MMA miniemulsion polymerizations significantly, enabling the synthesis of loaded nanoparticles. Nevertheless, adding the filters shifted the particle size distributions toward larger diameters, which are appropriate for cosmetic formulations. Based on the SPF analyses, it was also possible to observe a 12‐fold increase in the SPF values of the prepared formulations and an increase in the critical wavelength. Therefore, the in situ incorporation of distinct UV filters during miniemulsion MMA polymerizations constitutes a robust and versatile technology to produce PMMA nanoparticles loaded with UV filters for preparation of sunscreen formulations.