Modified Silica Nanoparticles Research Articles

Modified silica nanoparticles stabilized foam for enhanced oil recovery

Modified silica nanoparticles stabilized foam for enhanced oil recovery

Regenerative Superhydrophobic Coatings for Enhanced Performance and Durability of High-Voltage Electrical Insulators in Cold Climates.

Superhydrophobic coatings can be a suitable solution for protecting vulnerable electrical infrastructures in regions with severe meteorological conditions. Regenerative superhydrophobicity, the ability to regain superhydrophobicity after being compromised or degraded, could address the issue of the low durability of these coatings. In this study, we fabricated a superhydrophobic coating comprising hydrophobic aerogel microparticles and polydimethylsiloxane (PDMS)-modified silica nanoparticles within a PDMS matrix containing trifluoropropyl POSS (F-POSS) and XIAMETER PMX-series silicone oil as superhydrophobicity-regenerating agents. The fabricated coating exhibited a static contact angle of 169.5° and a contact angle hysteresis of 6°. This coating was capable of regaining its superhydrophobicity after various pH immersion and plasma deterioration tests. The developed coating demonstrated ice adhesion as low as 71.2 kPa, which remained relatively unchanged even after several icing/de-icing cycles. Furthermore, the coating exhibited a higher flashover voltage than the reference samples and maintained a minimal drop in flashover voltage after consecutive testing cycles. Given this performance, this developed coating can be an ideal choice for enhancing the lifespan of electrical insulators.

Improvement of the anti-corrosion coating properties of waterborne epoxy resin with the incorporation of fluoropolymer-modified silica nanofillers

The objective of this research was to enhance the corrosion resistance and mechanical properties of silica nanoparticles modified by a fluoropolymer (polyhexafluorobutyl acrylate, PHFBA) by incorporating them into a waterborne epoxy resin (WEP) coating system. Initially, polyhexafluorobutyl acrylate (PHFBA)-modified silica nanoparticles were synthesized using a two-step method, involving the grafting of 3-(isobutylloxy) propyl trimethoxysilane (KH570) onto SiO2 to produce SiO2@KH570, followed by a random copolymerization of SiO2@KH570 with hexafluorobutyl acrylate (HFBA) to obtain the fluoropolymer-modified SiO2 (FxSiO2). Subsequently, the chemical structure and elemental composition of SiO2, as well as the prepared SiO2@KH570 and FxSiO2 nanoparticles, were comprehensively investigated. Moreover, FxSiO2/WEP composite coatings with different amounts of fluoropolymer-modified nanofillers and x-F5SiO2/WEP composite coatings with varying amounts of F5SiO2 nanofillers were prepared and characterized. The findings revealed that the functionalized FxSiO2 exhibits superior dispersion, interface, and size effects, significantly enhancing the overall performance of WEP coatings. Notably, when 0.1 wt% F5SiO2 nanofiller was incorporated, the resulting 0.1-F5SiO2/WEP composite coating demonstrated a considerable impedance modulus (1.171 × 108 Ω∙cm2), relatively low water absorption rate (about 11 % after 20 d of immersion in water), and robust mechanical properties: a tensile strength of 6.07 MPa and an elongation at break of 37.36 %. Moreover, the hardness and adhesion of the composite coating remain unaltered. Furthermore, after 20 days of salt spray testing, the electrochemical impedance still reached 8.765 × 106 Ω∙cm2, indicating a favorable long-term anti-corrosion capability. Consequently, the integration of fluoropolymer-modified nanoparticles in water-based epoxy resins holds great potential.

A loose polyethersulfone hybrid nanofiltration membrane incorporated with polyethyleneimine-decorated silica nanoparticles for highly-efficient dye/salt separation

Loose nanofiltration (LNF) is a newly-developing technology for desalting dye-containing saline effluents, but suffers from membrane materials with low permeance and poor dye/salt separation selectivity. Herein, a hybrid polyethersulfone (PES) LNF membrane for dye/salt separation was prepared via a nonsolvent-induced phase inversion method, which was carried out using polyethyleneimine (PEI)-modified silica nanoparticles as a dopant. This design not only featured a hybrid PES LNF membrane with high porosity and small mean pore size, but also partially neutralized its charge and enhanced its hydrophilicity. Hybrid PES LNF membrane from a 21-wt% PES solution with 3-wt% PEI-decorated silica nanoparticles addition was demonstrated to achieve high water permeance (92.0 L m−2 h−1 bar−1) and dyes retention ratio (98.4 % for Congo Red, 98.8 % for Nile Blue A, and 95.1 % for Methyl Blue) accompanied with fully-pass for various salts (Na2SO4, NaCl, MgCl2 and CaCl2). In addition, the hybrid membrane exerted excellent resistances to strong acidic, oxidative and hot water (90 °C) environments and exhibited a pH-sensitive permeability. Multicycle test revealed that the hybrid membrane had high permeance recovery ratio (>92.8 %) and maintained its high dye retention and complete salt permeation even after 10 cycles, manifesting its outstanding fouling resistance and recyclability. Besides, the hybrid membrane repelled 92.6 % of dyes from a simulated wastewater consisting of multiple industry-applied direct dyes and salts after 12 h consecutive test, but allow 100 % of mixed salts passing through the membrane, proving its practical applicability to industrial dyeing wastewater. This study provided a simple and economically feasible route to high-performance LNF membrane production for dye/salt separation, thus popularizing LNF process in dyeing wastewater treatment, organic products purification, and resource recovery.

Interfacial Behaviors and Oil Detachment Mechanisms by Modified Silica Nanoparticles: Insights from Molecular Simulations.

Surfactant flooding has been considered as a promising approach for chemically enhanced oil recovery (EOR). However, this technique encounters several limitations, such as high costs, environmental concerns, and reduced efficiency under high-temperature and high-salinity reservoir conditions. Recently, nanoparticles have also been proposed as an alternative for EOR due to their superior properties compared with surfactants. This research employs molecular dynamics simulations to explore the impact of modified SiO2 nanoparticles on oil-water interfacial behaviors and the detachment of oil droplets from an oil-wet surface. The simulation results reveal that modified nanoparticles, featuring hydrophilic and hydrophobic functional groups, have slight impacts on interfacial tension reduction of the oil-water interface. Nanoparticles with varying degrees of modification exhibit distinct positions within the interface, consequently influencing the thickness of the interfacial layer. Notably, the interactions among the nanoparticles, oil molecules, and surface facilitate the formation of a water channel, thereby enhancing the process of oil detachment. Comparative analysis indicates that in terms of oil displacement efficiency, the thickness of the interfacial layer has a more significant impact than interfacial tension reduction. Furthermore, to elucidate the mechanisms of modified nanoparticles enhancing the oil recovery rate, the interaction energies among the oil droplet, nanoparticles, water, and surface are analyzed. The molecular-level insights derived from this investigation could provide valuable guidance for the design of modified nanoparticles tailored to EOR applications.

Bioaccessibility of chlorogenic acid and curcumin co-encapsulated in double emulsions with the inner interface stabilized by functionalized silica nanoparticles

The aim of this study was to evaluate the bioaccessibility of chlorogenic acid (CA) and curcumin co-encapsulated in Pickering double emulsions (DEs) with the inner interface stabilized by hydrophobically modified silica nanoparticles with myristic acid (SNPs-C14) or tocopherol succinate (SNPs-TS). Both SNPs-C14 and SNPs-TS showed contact angles > 90°. Pickering W1/O emulsions were formulated with 4 % of both types of SNPs. Pickering DEs showed higher creaming stability (5–7 %, day 42) and higher CA encapsulation efficiency (EE; 80 %) than control DE. The EE of curcumin was > 98 % in all the DEs. CA was steadily released from Pickering DEs during digestion, achieving bioaccessibility values of 58–60 %. Curcumin was released during the intestinal phase (∼80 % bioaccessibility in all DEs). Co-loaded DEs showed similar bioaccessibility for CA and curcumin than single-loaded. SNPs-C14 and SNPs-TS were suitable to stabilize the W1:O interface of DEs as co-delivery systems of bioactive compounds with health-promoting properties.

Preliminary Study on the Modification of Quantum Dots/Geothermal Silica Nanocomposites with Breast Cancer Antibody (MUC-1)

In this research, a silica-based nanosensor is synthesized using the sol-gel method and subsequently modified with quantum dots and MUC-1 antibody to detect MCF7, a cell line commonly found in breast cancer. Synthesis of silica nanoparticles was conducted through the sol-gel process using NaOH and HCl. The characterization using surface area analysis shows that geothermal silica based nanoparticles exhibit specific size of 31.2 nm with specific surface area of 192.37 m2/g. The nanoparticles were then modified using Cd-based Carboxyl Quantum dots to give fluorescence properties, obtaining SiNP@QD. Characterization was performed using UV-Vis and fluorescence spectroscopy to understand the photostability of nanoparticles in PBS buffer in various concentrations. The fluorescent nanoparticles were then immobilized with MUC-1 antibody and the successful conjugation was confirmed with FTIR showing peaks at 1548 and 1637 cm−1 corresponding to the amide I and amide II stretching vibration, respectively. The MUC-1 antibody modified silica nanoparticles is potential to be applied as nanosensor for the optical detection of MCF-7 cell line as one of breast cancer biomarkers.

Advances in modified silica nanoparticles utilization for various applications: Now and future

The review article explores the multifaceted applications of silica nanoparticles (SNPs) across diverse industries, emphasizing their catalytic role in transformative advancements. Green nanotechnology principles are crucial for sustainable SNP synthesis, with a focus on utilizing natural extracts and bio-agents. Standardization and enhanced collaboration between industry and academia are pivotal for realizing the broader potential of SNPs. In the biomedical realm, SNPs exhibit exceptional capabilities in drug delivery and diagnostics, promising significant medical advancements. Safe integration necessitates collaborative efforts in safety assessments, long-term studies, and standardized testing. The exploration of SNP-based advanced coatings hints at industry-specific applications, with a recommendation for continued research into new capabilities and compatibility. SNPs in Li-ion batteries show promise for energy storage, urging further investigation into scalability and long-term performance. Agriculture benefits from SNP applications in precision farming, emphasizing the need for environmentally conscious formulations. In nanocomposite materials, SNPs enhance mechanical properties, advocating collaborative research for standardization and optimization. The adaptability of SNP-based smart coatings in aerospace and automotive industries requires exploration of new functionalities and seamless integration. In conclusion, SNPs hold promising prospects in healthcare, energy storage, and agriculture, emphasizing the necessity of collaborative efforts, sustained research, and a commitment to responsible and innovative SNP integration for a technologically advanced and environmentally conscious future.

Synthesis and performance evaluation of temperature and salt-resistant organic/inorganic composite copolymers

ABSTRACT Ordinary polymers have poor adaptability in high-temperature and high-salt reservoir environments due to their properties. Organic/inorganic composite copolymer microspheres have the advantages of both of them, which are expected to break through their applicability limitations in such oil reservoirs. Therefore, its preparation and performance have always been of great concern to researchers. In this paper, AM/AMPS/Si-St ternary copolymers were synthesized by precipitation polymerization; then modified nano-silica particles were added to synthesize AM/AMPS/Si-St/g-SiO2 organic/inorganic composite quaternary copolymers. FT-IR and SEM characterized the copolymers to confirm that they were prepared successfully. Experiments were carried out to investigate the concentration and ratio of monomers, which showed that the Weissenberg effect could be avoided. The number of polymer molecules could be stabilized under AM concentration of 12 wt%, AM/AMPS/Si-St ratio of 8:1:1, nano silica of 3.3% and the modification conditions of KH570:SiO2 = 1:1. The experiments of temperature and salt resistance of two copolymers were evaluated and compared were conducted by using viscosity and particle size as parameters. The results showed that quaternary copolymers could increase the viscosity retention rate by about 10% compared with ternary copolymers under high content of Na+ and Mg2+. When the two copolymers were placed at 150°C, the appearance and morphology of the terpolymer changed obviously. Through the SEM image of the quaternary copolymers, it could be seen that although the spherical shape of the microsphere had been gradually lost, no degradation occurred, and the stable time of the modified microspheres had been effectively extended.

Transparent superhydrophobic coating for copper metal and study of surface morphology and antimicrobial characteristics

Nowadays, copper is a widely used metal worldwide for various applications such as electronic materials, electrical circuits, ornamentals and decorative applications. Copper is widely known for its antimicrobial properties. Despite this fact, it is found to be susceptible to biocorrosion. To protect the copper metal from biocorrosion, hydrophobically modified silica nanoparticles were prepared by the sol gel process. The Prepared sol solution was characterized by Particle size analysis, transmission electron microscopy (TEM) and infrared spectroscopy. Modified silica nanoparticles coated on the copper substrate to obtain superhydrophobic surface. Surface morphology was observed by scanning electron microscopy (SEM), electron dispersive microscopy (EDX) and atomic force microscopy analysis (AFM). Wettability and antimicrobial activity of the copper surface were also studied. The average particle size was found to be 96 nm and the formation of silica nanoparticle in the sol was also confirmed by IR spectra. The Contact angle of coated copper was found 163.3˚compared to 66.6˚ of uncoated copper surface which confirms the superhydrophobic behavior of the coated surface. The presence of nanostructured surfaces was responsible for superhydrophobic behavior which was confirmed by SEM and AFM studies. The coated copper showed excellent antimicrobial characteristics against E-coli.

Superhydrophobic polyether sulfone (PES) dialysis membrane with enhanced hemocompatibility and reduced human serum protein interactions: Ex vivo, in situ synchrotron imaging, experimental, and computational studies

This study aimed to enhance the hemocompatibility of polyethersulfone (PES) membranes by increasing their hydrophobicity. Two methods were used: chemical modification with a hydrophobic substance and creating a micropatterned structure using modified silica nanoparticles (SiO2 NP) in a mixed matrix membrane (MMM). Fibrinogen adsorption was assessed using synchrotron radiation micro-computed tomography (SR-µCT), and surface roughness was analyzed with atomic force microscopy (AFM). Hemocompatibility was evaluated by studying interactions with patients' serum and measuring the release of inflammatory biomarkers (C5a, IL-1α, IL-1β, IL-6, vWF, C5b-9 and PF-4). Differential Scanning Calorimeter (DSC) analysis determined the stability of the membrane hydration layer, and water contact angle (WCA) measurements assessed hydrophobic properties. Fourier-transform infrared spectroscopy (FTIR) and surface charge analysis examined surface stability. Molecular docking analysis showed reduced interaction between hydrophobized PES membranes and fibrinogen and albumin in human serum. SR-µCT analysis revealed 20% less fibrinogen adsorption on hydrophobized PES membrane surfaces. MMM PES membranes exhibited minimal fibrinogen adsorption due to the micropatterned structure. Both hydrophobized PES membranes demonstrated reduced vWF biomarker release (25–28%) compared to unmodified PES, with MMM PES membranes performing best. However, both hydrophobized PES membranes led to a significant increase (150%) in IL-6 upon blood contact, attributed to the reduced hydration layer. MMM PES membranes contained the least strongly bound water (0.2%) and exhibited the highest hydrophobicity (98°). This study highlights the potential of hydrophobized PES membranes and MMM structures for enhancing hemocompatibility, with opportunities for optimizing surface modifications to reduce inflammation responses while maintaining desirable properties.

Preparation and catalytic activity evaluation of a novel poly(ionic liquid)-modified silica nanoparticle

In this paper, a novel silica nanoparticle modified with a poly(ionic liquid) is synthesized by an ion exchange reaction and graft polymerization on the surface of the nanoparticle. By utilizing FT-IR, TGA, and TEM, the diverse products prepared are characterized. The modified silica nanoparticles are subsequently used as supporters to generate a catalyst containing Au. To evaluate the catalytic activity of the catalyst, methyl orange is degraded in the presence of H2O2. The results of the experiments indicate the catalyst possesses a level of catalytic activity comparable with that of TiO2 nanoparticles.

Enhancing the hemocompatibility of polyethersulfone (PES) hemodialysis membranes using synthesized pseudo zwittronic polymers with various orientations

The incompatibility of membrane materials with blood in the dialysis process has resulted in extensive number of side effects as well as undesired mortality rates for end-stage renal disease (ESRD) patients. Recent attention has been directed at enhancing the hemocompatibility of dialysis membranes. This study synthesized polyether sulfone (PES) mixed matrix membranes (MMMs) containing modified silica nanoparticles (SiO2 NPs) using the phase inversion technique. SiO2 NPs were modified with pseudo-zwitterionic (pZW) coatings of different structures. The modification of SiO2 NPs and their presence in casted MMMs were confirmed using Fourier-transform infrared (FTIR) spectroscopy. Molecular dynamics (MD) simulations were used to compute the quantity and energy of hydrogen bonds, which serve as a metric of hemocompatibility. Surface charge measurements were used to confirm the neutralization of the modified membrane surface charge. Atomic force microscopy (AFM) analysis revealed the influence of the structure of the SiO2 NPs on casted MMM surface roughness. The influence of the pZW coating structure on MMM hemocompatibility was examined in vitro using patient serum to investigate the inflammatory biomarkers released (C5a, IL-1α, IL-1β, IL-6, properdin, C5b-9). The clinicalex-vivo studies showed improvement of hemocompatibility in terms of IL-1α, IL-1β, Properdin, and C59-9. 5 % lower secretion of complement factor and interleukins reflected an improvement of hemocompatibility. Comparing MMM-1 to the other samples, the hemocompatibility profile was better. MD results were in agreement with the clinical outcomes as MMM-1 had the highest number of hydrogen bonds (8) and hydrogen bonding energy value (0.72 kcal/mol), indicating greater water interaction.

Computational design of nucleating agents of poly (methyl methacrylate) microcellular foams: “savanna‐like” surface structures and their effects on foaming

AbstractTo further the computational design of polymer foaming, this work investigated the interactions between polymer and nucleating agents by evaluating the removal forces needed to remove the polymer from the nucleating agent using molecular dynamics simulations. Silica nanoparticles modified with different organic groups and different surface modification ratios represented model nucleating agents and poly methyl methacrylate (PMMA), a model polymer. Modified organic groups with a certain length and flexibility grafted sparsely on the silica surface, creating a “savanna‐like” structure, increased the interaction between PMMA and the silica nanoparticle. The simulation results predicted the effects of the modified organic group and surface modification ratio R of the silica nanoparticle seen in actual batch foaming experiments using CO2 and PMMA with modified silica nanoparticles. Cell size shows a minimum and cell nucleation density a maximum in the foamed polymer under certain conditions, which correlate with the simulation results for the interactions between the polymer and nucleating agent. Based on the correspondence between the simulation and the experimental results, the effectiveness of such simulations for the design of nucleation agents appeared promising.Highlights Computational design of nucleating agents for microcellular foams. Evaluation of the interaction of polymers with various nucleating agents. Large interactions due to the “savanna‐like” structure of nucleating agents. Demonstration of polymer foaming with designed nucleating agents.

Functionalization of mesoporous silica with oligoisoprene brushes: Application as charge for elastomers reinforcement

The interfacial interaction between mesoporous silica nanoparticles (MSN) and natural rubber was successfully improved by surface modification of hydrophilic silica using oligoisoprene brushes. This approach involved grafting 3-aminopropyltriethoxy silane (APTES) onto the silica surface, achieving a grafting efficiency of 13.22 % and generating amine groups. The long polyisoprene chains of natural rubber were selectively cleaved using an optimized oxidative reaction, resulting in the formation of short oligomers with carbonyl chain ends known as Carbonyl Telechelic Natural Rubber (CTNR), having a molecular weight of 4100 g/mol. The CTNR oligomers were subsequently linked to APTES-modified silica via a Schiff's base reaction, imparting hydrophobicity to the silica surface and enhancing its compatibility and dispersion within the natural rubber matrix. Two conditions, MSN@CTNR1 and MSN@CTNR2, were investigated, exhibiting grafting efficiencies of 10.66 % and 4.70 %, respectively. The functionalized silica particles from MSN@CTNR1 were examined and incorporated at varying proportions into rubber latex, leading to the formation of thin films. Surprisingly, films containing 1 part per hundred rubber (phr) functionalized silica had better mechanical and thermal properties than films containing unmodified silica. This study underscores the potential of MSN, whose surfaces are modified by grafting oligoisoprene brushes, to enhance the crosslinking points and serve as innovative additives in the formulation of composite rubber films. Furthermore, these findings highlight the prospects of utilizing modified silica nanoparticles as coating additive materials, enabling the enhancement of properties and performance in rubber-based composites, thereby paving the way for the development of advanced coating applications in diverse industries.

Poly(2-n-propyl-2-oxazoline)/tannic acid nanocapsules with in-situ synthesized gold nanorods for cancer theranostics

The concept of hollow polymeric capsules fabricated with thermoresponsive polymers has revealed immense possibilities in the field of nanomedicine due to their tunable temperature and pH responsiveness caused by lower critical solution temperature (LCST) behavior. Herein, we report a new methodology to in-situ synthesize gold nanorods (AuNRs) within the pores of mesoporous silica nanoparticles (NPs) by trapping gold seed crystals and growing them into NRs in the presence of a weak reducing agent. The mesoporous silica NPs with incorporated NRs, i.e., modified silica NPs (SiO2-NRs) were used as sacrificial template for the fabrication of hollow polymeric multilayer capsules via layer-by-layer (LbL) assembly using poly(2-n-propyl-2-oxazoline) (PnPrOx) and tannic acid (TA) as layer components. The NRs of 25 ± 5 nm in size were uniformly distributed in the interior structure of PnPrOx/TA nanocapsules. The photo-thermal conversion efficiency of the PnPrOx/TA nanocapsules was found to be 47.5%. The release of encapsulated doxorubicin was found to be 55%, which increased to 68% when the incubation time was increased from 1 to 2 h. An on-demand burst release of 56% of the drug occurred within 2 min of NIR light exposure, and it reached 72% within 30 min, which inflicted major damage to cancer cells. Notably, the capsule suspension temperature increase from room temperature to 47 °C under laser light exposure, which is not only playing a key role in rupturing the capsules to enhance the drug release but also induces a hyperthermia effect in the tumor environment. Further, the in-vitro cytotoxicity experiments with human epithelial HEp-2 cells and fibrosarcoma HT1080 cells revealed an enhanced anti-cancer activity due to a synergistic chemo-photothermal effect. Hence, the proposed nanocapsule system can provide a unique, cheap, and efficient way of fabricating cancer theranostics for in-vivo applications.

Nanoparticles and polymers complexes as a harmless shale plugging inhibitor for ocean water-based drilling fluids

Due to the stringent environmental regulations that have been gradually proposed, the additives of WBDFs with low toxicity and degradability have become crucial. Clays and nano-micron fractures are the main causes of wellbore instability in ocean shale formations. In this paper, the plugging inhibitor was designed based on the skeletal structure of molecule, functional groups and molecular weight. Then the silane coupling agent was used to modify silica nanoparticles. And further the ZY-1 as a harmless plugging inhibitor was created by graft copolymerization of transition product and AA-AAK. These evaluation results demonstrated that ZY-1 not only was nontoxic and biodegradable, but also displayed a decent thermal stability (150 °C) and plugging inhibitive performance. What's more, this paper proposed the underlying inhibition and plugging mechanisms based on the structure and function of ZY-1.

Particle Size and Rheology of Silica Particle Networks at the Air-Water Interface.

Silica nanoparticles find utility in different roles within the commercial domain. They are either employed in bulk within pharmaceutical formulations or at interfaces in anti-coalescing agents. Thus, studying the particle attributes contributing to the characteristics of silica particle-laden interfaces is of interest. The present work highlights the impact of particle size (i.e., 250 nm vs. 1000 nm) on the rheological properties of interfacial networks formed by hydrophobically modified silica nanoparticles at the air-water interface. The particle surface properties were examined using mobility measurements, Langmuir trough studies, and interfacial rheology techniques. Optical microscopy imaging along with Langmuir trough studies revealed the microstructure associated with various surface pressures and corresponding surface coverages (ϕ). The 1000 nm silica particle networks gave rise to a higher surface pressure at the same coverage compared to 250 nm particles on account of the stronger attractive capillary interactions. Interfacial rheological characterization revealed that networks with 1000 nm particles possess higher surface modulus and yield stress in comparison to the network obtained with 250 nm particles at the same surface pressure. These findings highlight the effect of particle size on the rheological characteristics of particle-laden interfaces, which is of importance in determining the stability and flow response of formulations comprising particle-stabilized emulsions and foams.

Geothermal drilling using reprocessable shape memory polymer nanocomposite

The use of efficient lost circulation materials (LCMs) is essential to reducing fluid loss in geothermal wells. The purpose of this work is to assess novel reprocessable smart shape memory polyurethane (SMPU) LCMs based on SMPU silica nanocomposite for geothermal drilling. Improving the recyclability of SMPU LCMs enhances resource utilization and minimizes drilling fluid waste. The novel isocyanate/amino-terminated surface of the modified silica nanoparticles (MSNPs) was chemically incorporated into the polyurethane during the synthesis of SMPU nanocomposite using an in-situ two-step polymerization method. The results show that the chemically integrated MSNPs effectively reinforce the SMPU matrix by improving the dispersion of the silica nanoparticles relative to unmodified silica-SMPU nanocomposites. After three cycles of the shape memory test, MSNPs-SMPU showed remarkable shape memory stability with a shape recovery ratio of over 80%. Fracture sealing at conditions encountered in geothermal drilling demonstrated 4% higher sealing pressure for MSNPs-SMPU LCMs coupled with 11% lower fluid loss, which increased drilling procedure safety and environmental protection. MSNPs-SMPU LCMs offer excellent reprocessability without affecting the fracture sealing capability. On the other hand, commercial Mica LCMs showed an 83% drop in fracture sealing pressure in their third cycle owing to particle crushing.

47 Safe-by-Design Advanced Materials: A case Study on Paint Formulation

Abstract Paint formulations are complex mixtures of both dissolved and particulate components, both organic and inorganic. Amorphous silica nanoparticles are included to make the paint layer dirt-repellent. Over entire life cycle of the paints containing such silica nanoparticles, however, their complex multicomponent composition may raise several concerns as to their hazard when exposed to humans and environment, notably due to the potential release of the incorporated nano-objects. To mitigate such concerns, several Safe-by-Design target specifications can be performed to provide revised/modified paint formulations with reduced potential risk. Within EU H2020 funded project, HARMLESS (grant agreement 953183), a specific industrial case study focuses on worker exposure measurement at the industrial production site of silane modified silica nanoparticles and consumer exposure measurement during sanding of the painted surfaces containing such silica nanoparticles. First results indicate that the tested paint samples (with and without silica nanoparticles) have strong tendencies to generate airborne nano-objects during their sanding. However, the fraction of silica in the overall chemical composition of the airborne nano-objects is currently being investigated. A fraction of the dust generated during the paint sanding is being analysed for its hazard via advanced in vitro approaches combined with a battery of toxicological endpoint analyses. Based on the results, if the exposure concentration of silica nanoparticles is found to be exceeding its nano reference value (i.e. 40,000 cm-3 TWA) and exhibits deleterious biological impact, the size and surface of silica nanoparticles will be modulated accordingly by keeping an optimum balance between their functionality and risk