Number Average Diameter Research Articles

Micro-mechanism analysis of the rheological properties of water-in-waxy-crude-oil emulsion under pipe flow

Flowing experiments with different water contents in water-in-waxy-crude-oil emulsions were performed in a flow loop apparatus. The real-time variations of rheological properties and microscopic distributions of the emulsions over time during pipe flow were quantitatively analyzed. It was found that the emulsification effect of the emulsion is enhanced due to shear effect, resulting in an increase of gel point and viscosity over time. The average increments in the gel point are approximately 1.5 °C, 1.7 °C and 1.9 °C for the emulsions with water contents of 10%, 20% and 30%, respectively. During the experimental period from 0.5 h to 18 h, the average viscosities measured at the emulsion temperature increase by 31%. Characterization parameters of number-averaged diameter (d 1,0), specific surface area (SA) and polydispersity (PDI) were applied to reflect the microstructure of emulsions from the perspectives of droplet size, dispersity and nonuniformity. The water droplets become smaller and uniformly dispersed as the pipe flow goes on. The Gibbs free energy increases as the emulsion flows through the pipe, which is mainly caused by the shear of the pipe wall. The van der Waals force increases from −0.0678 × 10−21 J to −1.7657 × 10−21 J as the emulsion’s water content changes from 10% to 30%. The water droplets can promote crystallization of wax crystals by offering the necessary nucleus surface. Furthermore, the coexistence of water droplets and wax crystals creates a synergistic effect, which can augment the total energy and structural strength of the emulsion system.

Polymeric nanoparticles for selective protein recognition by using thiol-ene miniemulsion photopolymerization

The fabrication of molecularly imprinted nanoparticles (MIP-NPs) specific for myoglobin by using thiol-ene photopolymerization in miniemulsion was described. Allyl derivatives of phenylalanine as a functional monomer was synthesized and copolymerized with acrylic monomers via miniemulsion polymerization to produce NIP-NPs with approximately 74 nm number average particle diameter. FTIR and 1H-NMR analysis confirmed the synthesis of functional monomer. MIP-NPs were prepared in the existence of myoglobin as a template protein. Morphological investigations exhibited that the particle size of the MIP-NPs, increased compared to the corresponding NIPs and the mean particle diameter by number was measured as 141 nm with narrow distribution. NIP-NPs that were polymerized without myoglobin were found to have less affinity to the target protein. In addition, the rebinding ability of MIP-NPs was much bigger than that of the corresponding NIPs. ELISA results showed that MIPs interact particularly with the myoglobin and show little affinity for BSA in competitive binding experiments.HighlightsAllyl N,N-diallyl phenylalaninate was synthesized as a functional monomer.Imprinted nanoparticles were prepared by using thiol-ene photopolymerization in miniemulsion.The nanoparticles were 141 nm with narrow size distribution.The imprinted nanoparticles showed selectivity toward myoglobin.

A study of the evolution of nanoparticle dynamics in a homogeneous isotropic turbulence flow via a DNS-TEMOM method

In this article, a coupling of the direct numerical simulation (DNS) and the population balance modeling (PBM) is implemented to study the effect of turbulence on nanoparticle dynamics in homogenous isotropic turbulence (HIT). The DNS is implemented based on a pseudo-spectral method and the PBM is implemented using the Taylor-series expansion method of moments. The result verifies that coagulation due to turbulent shear force has a bigger impact on the evolution of number concentration, polydispersity, and average diameter of nanoparticles than Brownian coagulation in the HIT. The Reynolds number plays an important role in determining the number concentration, polydispersity, and average diameter of nanoparticles, and these quantities change more rapidly with an increase of Reynolds number. It is also found that the initial geometric standard deviation slows down the evolution of particle dynamics, but almost has no influence on the polydispersity of nanoparticles.

Semiconducting polypyrrole@TiO2 pure anatase nanoparticles for photodegradation of reactive red 120 azo dye

In the recent years, the development of new and efficient materials for photocatalytic processes has been of growing interest for applications in wastewater treatment. In this sense, TiCl4 stabilized with H2SO4 was precipitated with ammonium hydroxide in the presence of sodium dodecyl sulfate and calcined to obtain thermally stable TiO2 nanoparticles, which were subsequently coated with semiconducting polypyrrole (PPy) by chemical oxidation resulting in a composite of TiO2@PPy. TiO2 and TiO2@PPy composite were characterized by SEM, Raman, XRD, UV/Vis–NIR, FTIR and TGA. It was observed that TiO2 consisted of spherical nanoparticles with number-average particle diameter of 19.2 nm and polydispersity index in sizes of 1.2, whereas TiO2@PPy composite consisted of agglomerated spherical PPy nanoparticles of number-average diameter of 182.4 nm coating TiO2 nanoparticles. The calculated optical bandgap of TiO2 was 3.07 eV, and it was demonstrated by the Rietveld refinement method of the XRD spectrum and from the Raman analysis that synthesized TiO2 corresponds to highly pure rhombic anatase crystal structure. TiO2@PPy composite was tested in the photodegradation of the reactive red 120 azo dye in aqueous solutions under visible light irradiation. It was observed that photodegradation rate increased with decreasing the initial dye concentration and increasing the composite load. Almost 100% of dye removal was achieved after 45 min of reaction for 20 mg L−1 of initial dye concentration and 1.0 g L−1 of composite load.

THE STUDY OF LOW-LACTOSE MILK WHEY STRUCTURE AND MODEL SYSTEMS ON ITS BASIS

This study developed a technology of low-lactose semi-finished products, based on fermented whey and pumpkin pulp puree, and offered a possibility of its use in the technology of structured culinary products. This research carried out the required substantiation of the methods of preliminary processing of raw materials, and studied the technological properties and structure of model compositions with their use. During the experiment, a number of studies were carried out, which substantiated the method and modes of condensation of whey, and provided a comparative analysis of the homogeneity of lactose-free and lactose-containing samples of whey under various modes of condensation. The study obtained the results of calculations of the equivalent diameter of the studied samples of lactose-containing and low-lactose whey, condensed by the contact method and in vacuum. It was found, that the structure is homogeneous at a number average crystal diameter of up to 5 μm. The restriction is valid for CLLWV with a calculated diameter of about 3.84 μm with a coefficient of variation of 1.35 % with an increase of 10,000 times. The study revealed the alternation of smooth and granular sections of the micron level (0.1 ... 5 μm) in the structure of the studied low-lactose semi-finished product with an increase of 300 times. It was determined, that the extremum of the differential curve of the particle size distribution of CLLWV corresponds to the number average crystal diameter of 3.84 μm. It was established, that the most homogeneous fractional composition is inherent in the studied sample of CLLWV, for which the values of fraction diameters are in the range from 1.46 μm to 4.96 μm. The optimal ratio of the components of the model CLLWV: FPPP system was determined as 70 % to 30 % respectively. With this composition, the model system is characterized by the formation of protein-pectin complexes, which is confirmed by microscopy with a magnification of 90 times

Simple and immediate quantitative evaluation of dispersive mixing

A dimensionless mixing number is developed to quantify dispersive mixing in a simple and immediate way. This takes into account number-average diameter, volume-average diameter and interfacial area simultaneously. It is an experimentally determined number, meaning the calculations are performed using microscopy images. This parameter was validated using various polymer blends (droplet morphology) and composite systems and can be used to compare various technologies on the basis of dispersive mixing efficiency.

Microemulsions based on polyglycerol polyricinoleate as drug delivery systems

The aim of the work is to develop composition of reverse microemulsion stabilized by the surfactant from a number of polyglycerol polyricinoleates for encapsulating water-soluble biologically active substance (BAS) and studying the kinetics of its release into the medium simulating the medium of the small intestine. Materials and methods. Possible stable (equilibrium) phases of the reverse microemulsion in the pseudoternary system water–PG-3-PR/Tween 80–paraffin oil were determined by titration of surfactant/co-surfactant mixtures–oil in water with hydrophilic-lipophilic balance (HLB) values of the surfactant mixture ranging from 4.0 to 7.0. Stability of a number of compositions during storage at 20 °C for 6 months was studied. Based on the obtained data, a composition was selected for encapsulating methylene blue (MS) dye as a model of a water-soluble biologically active substance. Microemulsion was obtained by mixing paraffin oil and surfactants with selected mass ratio followed by the addition of an aqueous phase. Reverse microemulsion morphology was evaluated with transmission electron microscopy (TEM). To evaluate the in vitro drug release rate, aliquots of an aqueous dye solution (control sample) and MB-containing microemulsions were placed in dialysis bags and immersed in 0.01 M phosphate-buffered saline (PBS) (pH 7.4) in a thermostatic shaking incubator at 180 rpm and 37 °C. Aliquots of the release medium were selected at predetermined time intervals and the concentration of MB dye was determined using a UV spectrophotometer at 660 nm. Results. Composition containing 13.5 wt% paraffin oil, 76.5 wt% mixture of PG3-PR/Tween 80 (HLB 5.5) and 10 wt% water was chosen to encapsulate the biologically active agents. Number average droplet diameter in the dispersed phase of the obtained microemulsion was 55 nm. Dye-loaded microemulsion sample showed a prolonged release of biologically active substances within 48 hours of the experiment (15.2%) and low initial release rate. Conclusion. Possible stable phases of reverse microemulsion in the pseudoternary system water–PG-3-PR/Twin 80–paraffin oil were determined in the course of the work and optimal microemulsion composition for encapsulating medicinal substances was found. It was shown that the resulting microemulsion system provides a sustained release of methylene blue as a model of a water-soluble biologically active substance in a medium simulating medium of the small intestine. The obtained data allow to consider this composition as a potential nanoscale system for the sustained delivery of water-soluble drugs.

A Two-Dimensional Heterogeneous Model of Lithium-Ion Battery and Application on Designing Electrode with Non-Uniform Porosity

In this work, a two-dimensional heterogeneous model of lithium-ion battery electrode is developed. The electrode is reconstructed using a non-volume-averaging approach, generating a heterogeneous structure in which solid and liquid phase are characterized separately with respective real spatial occupation and boundaries between them. The heterogeneous model is parameterized using voltage and temperature curves at multiple C-rates. Mass and charge transport in the generated electrodes, coupled with interfacial reactions, are numerically solved. Three cases with different porosity profiles are compared. Without changing the amount of active materials and its particle size distribution, an improvement of rate performance up to 50% is achieved in the case with larger electrode porosity near the electrode-separator interface. Using the heterogeneous model as the benchmark, the precision of the pseudo-two-dimension model of lithium-ion battery electrode, which has been widely adopted in literatures and commercial computational softwares, can be improved by proper parameterization, including using the volume-averaged rather than number-averaged diameter as the negative electrode particle size; using the generated electrode structure, rather than the Bruggeman relationship, to calculate the tortuosity of porous electrodes; and using the size of primary particle, rather than that of the agglomerate, as the particle size at the positive electrode.

Modelling of particle size distribution in butyl acrylate emulsion polymerisation in a batch reactor

ABSTRACT A computer model for the development of particle size distribution in a batch reactor for the emulsion polymerisation of butyl acrylate was developed, solved and validated. Population balance model was represented by partial differential equations and these equations were solved by using the method of orthogonal collocation. The model was validated against two sets of experimental data taken from literature. The model’s reliability was demonstrated by successful simulation of the experimental data for the number of variables which included the number of particles formed at different emulsifier and initiator concentrations, the variation of conversion with time at one initiator concentration and one emulsifier concentration and number average diameter, volume average diameter at different emulsifier concentrations. The model is simpler and more accurate than the reported population balance models for this system in the literature. The simplicity is brought by studying the model in different levels of details in our earlier works.

Liquid Marbles in Nature: Craft of Aphids for Survival.

Some aphids that live in the leaf galls of the host plant are known to fabricate liquid marbles consisting of honeydew and wax particles as an inner liquid and a stabilizer, respectively. In this study, the liquid marbles fabricated by the galling aphids, Eriosoma moriokense, were extensively characterized with respect to size and size distribution, shape, nanomorphology, liquid/solid weight ratio, and chemical compositions. The stereo microscopy studies confirmed that the liquid marbles have a near-spherical morphology and that the number-average diameter was 368 ± 152 μm, which is 1 order of magnitude smaller than the capillary length of the honeydew. The field emission scanning electron microscopy studies indicated that micrometer-sized wax particles with fiber- and dumpling-like shapes coated the honeydew droplets, which rendered the liquid marbles hydrophobic and nonwetting. Furthermore, the highly magnified scanning electron microscopy images confirmed that the wax particles were formed with assemblage of submicrometer-sized daughter fibers. The contact angle measurements indicated that the wax was intrinsically hydrophobic and that the liquid marbles were stabilized by the wax particles in the Cassie-Baxter model. The weight ratio of the honeydew and the wax particles was determined to be 96/4, and the honeydew consisted of 19 wt % nonvolatile components and 81 wt % water. The 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, and mass spectroscopy studies confirmed that the wax mainly consisted of triglycerides and that the honeydew mainly consisted of saccharides (glucose and fructose) and ribitol. The atomic force microscopy studies confirmed that honeydew is sticky in nature.

Effects of Ethanol Addition on the Size Distribution of Liposome Suspensions in Water

Understanding the influence of ethanol on liposomes is important for insights into the physiological effects of ethanol on cell membranes and for transdermal drug delivery. In this work, different amounts of ethanol are added to liposome suspensions (1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes) of different initial sizes, and the size distributions are measured using dynamic light scattering. The average diameter reduces by 5–6% at a concentration of 20 vol % of ethanol, and the size distributions with and without ethanol are identical when scaled with the number-average diameter. The observed changes in diameter are significantly larger than the standard error of the measurements. Dilution of the liposome suspension containing 20 vol % ethanol with addition of water causes the liposomes to nearly regain their original size at that concentration; thus, the size change is reversible. The size measurements from dynamic light scattering are validated by cryo-transmission electron microscopy measurements, which show a similar reduction in the number-average diameter. ³¹P NMR studies also show a reduction in size upon addition of ethanol. The volume fraction of liposomes in the suspension, obtained from viscosity measurements, decreases by 9% with ethanol addition. A reduction of 4% in the number-average diameter is obtained upon adding 20 vol % ethanol to a suspension of giant liposomes, with the size distributions obtained by optical microscopy. Addition of cholesterol in the lipid membrane reduces the extent of shrinkage. The results indicate that the size reduction is due to shrinkage of liposomes and not due to breakage or dissolution and that the shrinkage is independent of the membrane curvature. Analysis shows that the decrease in size cannot be ascribed to membrane undulations alone when the increase in area per lipid molecule due to ethanol is taken into account. Addition of ethanol during the preparation of liposomes results in a much larger reduction in the average liposome diameter (up to 20%).

Si-containing 9Cr ODS steel designed for high temperature application in lead-cooled fast reactor

The oxide-dispersion strengthened (ODS) ferritic steels have been considered as promising candidate structural materials for liquid lead-bismuth eutectic (LBE) cooled reactors, and the corrosion of the ODS steel in liquid LBE presents a critical challenge. In order to improve the corrosion resistance of the ODS steel, a type of Y-Si-O strengthened ODS steel was designed and fabricated. The grain structure and dispersed nanoparticles were carefully characterized by the scanning electron microscope (SEM), the transmission electron microscope (TEM), the high-resolution transmission electron microscope (HRTEM) and the atomic probe tomography (APT) methods. Y2Si2O7 and Y2SiO5 nanoparticles both with monoclinic cubic crystal structure were found to be dominated in the matrix. And the number density and average diameter of the distributed nanoparticles were counted to be 1.8 × 1024 m−3 and ∼6 nm, respectively. The three dimensions APT reconstruction revealed that the as-received ODS alloy contained a high number density of nanometer scale yttrium-, silicon-, vanadium-, and oxygen-enriched nano-particles Furthermore, the high temperature property and corrosion resistance of the ODS steel were evaluated preliminarily. The miniature specimen tensile tests performed at 550 °C showed satisfactory high tensile strength of the ODS steel. The corrosion resistance was significantly improved by the addition of silicon according to the test of 1000 h exposure to liquid LBE.

Grinding mechanism and mechanical properties of the in-situ synthesized Al2O3/TiAl composites

Abstract In-situ synthesis of Al2O3/TiAl composite was carried out by mechanical milling of the pre-alloy Ti-45Al-7Nb-0.3W and TiO2 powder mixture and subsequent sintering by spark plasma sintering (SPS) technique. The mixed powders experienced the initial destructive breakage stage, cold welding package stage and breaking up of boulders stage during mechanical milling. The particle size obviously declined with the mechanical milling time increasing. The number-average diameter (D(1,0)) of as-milled powders rapidly reduced from 75.0 μm to about 15.5 μm, and its distribution uniformity (U) decreased to 0.55 when milling time increased to 20 h. Nano Al2O3 particles had been formed during milling. The as-SPSed compacts were mainly composed of γ-TiAl phases, α2-Ti3Al phases and nano-Al2O3 particles that tended to disperse both on the grain boundaries and inside the lamellar microstructure of the matrix. The contents of A12O3 increased from 4.3% to 8.9 vol% as the milling time increased from 10 to 20 h. The increasing concentration led to the increase in Vickers hardness of Al2O3/TiAl composites, and a maximum value of 6.2 GPa was achieved. A corrected mixture rule was constructed which can predict the hardness of the composites accurately. The ultimate compression strength (UCS) increased firstly and then decreased with prolonging milling time. The highest value of 1848 MPa was obtained when the mixed powders milled for 15 h, i.e., the fraction of Al2O3 in the TiAl matrix was 7.6 vol%.

Using a DiSCmini classifier for real-time determination of ultrafine particle mass concentration—application to diesel particle measurement

Exposure to ultrafine particles (particle diameter < 100 nm) in workplace atmospheres requires direct-reading measuring instruments. The DiSCmini (Testo®) is a portable device designed for the real-time measurement of particle number concentration and average diameter. However, exposure to airborne particles is traditionally expressed in terms of mass concentration; this knowledge of mass also allows comparison with other measurement methods as well as occupational exposure limits. In this study, the mass concentration was determined from the two parameters measured by the DiSCmini, i.e., the number concentration and the average diameter. The calculation of the mass concentration was made possible by taking into account particle number size distribution and effective density. Different approaches were considered to simplify the calculations as much as possible. These approaches were tested in the laboratory with combustion test aerosols generated from a diesel engine.

Critical Size Limit of Biodegradable Nanoparticles for Enhanced Lymph Node Trafficking and Paracortex Penetration.

Lymph node (LN) targeting through interstitial drainage of nanoparticles (NPs) is an attractive strategy to stimulate a potent immune response, as LNs are the primary site for lymphocyte priming by antigen presenting cells (APCs) and triggering of an adaptive immune response. NP size has been shown to influence the efficiency of LN-targeting and retention after subcutaneous injection. For clinical translation, biodegradable NPs are preferred as carrier for vaccine delivery. However, the selective "size gate" for effective LN-drainage, particularly the kinetics of LN trafficking, is less well defined. This is partly due to the challenge in generating size-controlled NPs from biodegradable polymers in the sub-100-nm range. Here, we report the preparation of three sets of poly(lactic-co-glycolic)-b-poly(ethylene-glycol) (PLGA-b-PEG) NPs with number average diameters of 20-, 40-, and 100-nm and narrow size distributions using flash nanoprecipitation. Using NPs labeled with a near-infrared dye, we showed that 20-nm NPs drain rapidly across proximal and distal LNs following subcutaneous inoculation in mice and are retained in LNs more effectively than NPs with a number average diameter of 40-nm. The drainage of 100-nm NPs was negligible. Furthermore, the 20-nm NPs showed the highest degree of penetration around the paracortex region and had enhanced access to dendritic cells in the LNs. Together, these data confirmed that small, size-controlled PLGA-b-PEG NPs at the lower threshold of about 30-nm are most effective for LN trafficking, retention, and APC uptake after s.c. administration. This report could inform the design of LN-targeted NP carrier for the delivery of therapeutic or prophylactic vaccines.

Breakage of vesicles in a simple shear flow.

The breakage of micron-size SOPC lipid vesicles in an aqueous suspension was studied in a simple shear flow over a range of shear rates (1000 s-1 to 4000 s-1). Evolution of the vesicle size distribution with time was determined using optical microscopy. The number average vesicle diameter was found to reduce continuously with time; at the highest shear rate (4000 s-1), the reduction was 38% after 6 h of shearing. The distributions indicated the existence of a critical diameter such that the number of vesicles larger than the critical diameter decreased and vesicles smaller than the critical diameter increased. The capillary number for the system (ratio of the characteristic viscous stress to the characteristic stress for stretching the lipid membrane) was two orders of magnitude lower than the values reported for breakage in an ultrasonically generated flow, indicating that vesicles do not rupture due to lysis of the membrane. Direct observation of the process in a shear cell fitted in a microscope stage revealed the mechanism of rupture. Measurements of the vesicle dimensions indicated an increase in aspect ratio with time as a result of leakage of fluid from inside vesicles. Once the aspect ratio increased above a threshold value, the vesicles elongated into long thread-like shapes, which broke into small daughter vesicles by pearling.

Obtaining of aluminum nano-powders by thermal treatment

It is known that the formation of a dispersed phase under extreme conditions (high temperatures andprocess speed) leads to the formation of a non-equilibrium structure of particles. Therefore, the first toattract attention are technologies based on pulsed processes with high rates of change in the thermodynamicparameters of the system. One of these promising methods for obtaining a wide range of nano-powders ofinorganic materials is the technology based on the process of electrical explosion of a conductor (EVP, EVPtechnology) [1-5]. Unfortunately, this method is not applicable on industrial scales. In this thesis, productionof Al nanoparticles by hydrogen reduction of metal chlorides in gas phase was studied. Nanoparticles haveunique properties not found in bulk or micron-scale materials. These enable new products or reduced useof raw materials. Metal nanoparticle production has been studied widely, but especially for coated metalparticles, research of coating mechanisms and economic production methods is still needed. The usedmethod combines a high yield, a high production rate, low production costs, high particle quality, and agood range of available particle number average diameters and other properties. Control of the productparameters has been carried out by using a special quenching system and plasma reactor configuration.Highly hydrogen enriched Al nanopowder were collected in metal form and tested for different applications.

Improving the textural properties of camel milk acid gel by treatment with trisodium citrate and transglutaminase

This study aimed to solve the problems of the weak acid-induced gelation ability of camel milk by the synergistic effect of trisodium citrate and microbial transglutaminase (mTGase). As the trisodium citrate concentration increased from 0 to 30 mmol/L, the final storage modulus of mTGase-treated camel milk acid gels increased from 11.9 ± 0.3 to 72.5 ± 2.4 Pa, the firmness increased from 0.7 ± 0.2 to 1.8 ± 0.1 N, and water holding capacity increased from 41.0 ± 1.8% to 99.6 ± 0.8%. A denser gel network structure with the smallest pore size was observed with 30 mmol/L trisodium citrate, which was selected as the optimum concentration. The number average diameter of the casein particles decreased significantly from 183.5 ± 5.9 to 37.4 ± 3.0 nm and the degree of crosslinking of the acid gel increased significantly from 19.3 ± 1.2% to 38.9 ± 2.4% in the presence of trisodium citrate. This study indicated that smaller casein particles with a higher level of covalent crosslinking can form a camel milk gel with better textural properties, which has enormous potential for manufacture of acid-induced camel milk gel products.

Model construction of particle size in dynamic vulcanization of PVDF/SR blends—matching degree between crosslinking and shearing rates

Abstract Peroxide-induced dynamic vulcanization of poly (vinylidene fluoride)/silicone rubber (PVDF/SR) blends was studied in this paper. We controlled the size of rubber particles by changing the rotor speed, and discussed the influence of shearing on the particle diameter and the particle diameter polydispersity (dp). The size of SR particle was confirmed to be decreased with increasing the rotor speed. However, a good matching degree of shearing and crosslinking rate helped the SR phase to achieve a uniform crosslinking, as well as a narrow dp. In this particular PVDF/SR system, the suitable rotor speed was found to be 90 rpm, at which the dp reached a minimum of 1.1981 and 1.1614 for the P9S1 and the P7S3, respectively. At last, we discussed the influences of the macroscopic breaking energy (Edk) and the coalescence (P) on the number-average particle diameter (Dn) of the SR. This work is thus devoted to construct a model for predicting the particle size in dynamic vulcanization of PVDF/SR blends.

Encapsulation ofN,N‐diethyl‐meta‐toluamide (DEET) via miniemulsion polymerization for temperature controlled release

ABSTRACTN,N‐diethyl‐meta‐toluamide (DEET), an insect repellent, can be successfully encapsulated in poly(n‐butyl methacrylate‐co‐methyl methacrylate) nanospheres via direct miniemulsion polymerization. Stable and low polydisperse nanospheres with a number average diameter of 114 ± 37 nm were obtained. It is shown that DEET is an effective costabilizer and that sodium lauryl sulfate is a suitable surfactant. The nanospheres glass‐transition temperature (Tg) can be tuned by adjusting the ratio betweenn‐butyl methacrylate and methyl methacrylate in the monomer formulation. The repellent reduced the polymerization reaction rate and the copolymer molecular weight, and changed the nanoparticle morphology. The release rate of the encapsulated DEET provides repellency for over 9 h and is and more controlled when compared to the free DEET. Results show the mechanism of release is temperature dependent. At temperatures close to and lower than the polymerTg, polymer relaxation is the limiting mechanism. At higher temperatures, Fickian diffusion limits the overall release. Thus, the DEET release rate can be tuned by adjusting the copolymerTg. This ensures this material a great potential as temperature‐dependent delivery system. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47139.