Rafael Muñoz-Espí

Rafael Muñoz-Espí
University of Valencia | UV · Institute of Materials Science (ICMUV)

PhD

About

106
Publications
15,414
Reads
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2,194
Citations
Citations since 2016
52 Research Items
1589 Citations
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
2016201720182019202020212022050100150200250
Introduction
Current research interests: colloidal methods for preparation of polymer particles; polymer/inorganic hybrid nanoparticles; interaction of polymers with inorganic matter; crystallization under confinement
Additional affiliations
May 2021 - present
University of Valencia
Position
  • Professor (Associate)
September 2020 - May 2021
University of Valencia
Position
  • Professor (Assistant)
September 2015 - August 2020
Max Planck Institute for Polymer Research
Position
  • Researcher

Publications

Publications (106)
Article
Calcium phosphate (CaP) deposition during bone mineralization starts with the aggregation of Posner’s clusters Ca9(PO4)6 into amorphous Ca-phosphate (ACP), which then transforms into crystalline CaP and finally maturates to hydroxyapatite (HA). Using dentin/enamel of human teeth as a model system, we show that the physiological inorganic polymer po...
Article
Silver-coated polymer nanocomposites have a broad range of applications, such as optical sensors and anti-microbial coatings. Here, silver ions were reduced in situ, on the surface of carboxylated polystyrene particles to synthesize silver-coated polystyrene particles. Silver ion-to-hydrazine (reducing agent) concentration ratio was identified as a...
Article
We report the preparation of a hybrid chitosan/silica three-dimensional (3D) scaffold loaded simultaneously with two model hydrophilic substances, ibuprofen sodium salt and erioglaucine disodium salt. The first substance is entrapped in situ during the preparation of chitosan submillimetric beads by ionotropic gelation with sodium triphosphate, whi...
Article
Full-text available
The SARS-CoV-2 infection is transmitted by respiratory droplets. We have introduced a new concept of masks, which comprises a threefold mode-of-action: trapping of the virus particles, blocking of the viruses, and finally killing of the viruses.
Article
Nanoemulsions are kinetically stabilized emulsions with droplet sizes in the nanometer scale. These nanodroplets are able to confine spaces in which reactions of polymerization or precipitation can take place, leading to the formation of particles and capsules that can act as nanocarriers for biomedical applications. This review discusses the diffe...
Article
This work reports an in situ strategy for the synthesis of hybrid sub‐millispheres as carriers for encapsulating and controlling the release of hydrophilic pharmaceutical compounds in both neutral and acidic media. An organic–inorganic hydrogel is prepared by ionotropic gelation, and its efficiency for entrapping hydrophilic molecules is investigat...
Article
Hydrated inorganic salts are phase change materials (PCMs) with promising thermal energy storage capacity. However, their application is commonly restricted because of problems of phase segregation, incongruent melting, cycling instability, or supercooling. This work presents an encapsulation method of hydrophilic PCMs that allows for the incorpora...
Article
Amorphous Ca-phosphate (ACP) particles stabilized by inorganic polyphosphate (polyP) were prepared by co-precipitation of calcium and phosphate in the presence of polyP (15% [w/w]). These hybrid nanoparticles showed no signs of crystallinity according to X-ray diffraction analysis, in contrast to the particles obtained at a lower (5% [w/w]) polyP c...
Article
Energy harvesting through residual heat is considered one of the most promising ways to power wearable devices. In this work, thermoelectric textiles were prepared by coating the fabrics, first with multiple-wall carbon nanotubes (MWCNTs) by using the layer-by-layer technique, and second with poly(3,4-ethylenedioxythiophene) (PEDOT) deposited by el...
Cover Page
The use of miniemulsions containing chemical precursors in the disperse phase is a versatile method to produce nanoparticles and nanostructures of different chemical nature, including not only polymers, but also a variety of inorganic materials. The focus is on materials in which nanostructures of metal oxides are synthesized in processes that invo...
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Full-text available
The distinguished property of the physiological polymer, of inorganic polyphosphate (polyP), is to act as a bio-intelligent material which releases stimulus-dependently metabolic energy to accelerate wound healing. This characteristic is based on the bio-imitating feature of polyP to be converted, upon exposure to peptide-containing body fluids, fr...
Article
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The use of miniemulsions containing chemical precursors in the disperse phase is a versatile method to produce nanoparticles and nanostructures of different chemical nature, including not only polymers, but also a variety of inorganic materials. This minireview focuses on materials in which nanostructures of metal oxides are synthesized in processe...
Article
Full-text available
There is a strong interest in cement additives that are able to prevent or mitigate the adverse effects of cracks in concrete that cause corrosion of the reinforcement. Inorganic polyphosphate (polyP), a natural polymer that is synthesized by bacteria, even those on cement/concrete, can increase the resistance of concrete to progressive damage from...
Article
The heterogeneous catalysis of the hydration of nitriles to amides is a process of great industrial relevance in which cerium(IV) oxide (also referred to as ceria) has shown outstanding catalytic performances. The use of non-supported ceria nanoparticles is related to difficulties in the purification of the product and the recovery and recyclabilit...
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Full-text available
Hybrid thermoelectric flexible films based on poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles and carbon nanotubes were prepared by using layer-by-layer (LbL) assembly. The employed PEDOT nanoparticles were synthesized by oxidative miniemulsion polymerization by using iron(III) p-toluenesulfonate hexahydrate (FeTos) as an oxidant and poly(di...
Article
Synthesis of n-type organic semiconductors is challenging as reduced states are difficult to obtain due to their instabil-ity in air. Here, we report tailoring of semiconducting behavior through control of surfactant concentration during synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles. Nanoparticles were synthesized by mini-emul...
Chapter
In the last two decades, electrospinning has grown in popularity; however, the majority of the setups are based on solution processing from toxic organic solvents. As green processing and environmental stewardship have also become important in recent years, for political and economic reasons, the subsequent increase in demand for the scaling up of...
Chapter
“Green Electrospinning” not from only non-toxic solvents but also from biopolymer solutions has become popular in recent years. Green fibers are particularly interesting for biomedical applications such as tissue engineering, drug delivery, biocompatible scaffolds, biosensors, and for photovoltaics, supercapacitors, fuel cells, battery components a...
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A new biomimetic strategy to im prove the self-healing properties of Portland cement is presented that is based on the application of the biogenic inorganic polymer polyphosphate (polyP), which is used as a cement admixture. The data show that synthetic linear polyp, with an average chain length of 40, as well as natural long-chain polyP isolated f...
Article
Zinc ferrite (ZnFe2O4) spinel nanocrystals were synthesised through three different low-temperature routes, namely hydrothermal, combined miniemulsion–hydrothermal, and microwave-assisted non-aqueous sol–gel synthesis. With the aim to study the influence of the respective approach on the structural evolution of the compounds during the synthetic pr...
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Full-text available
The fabrication of two-dimensional (2D) biomineral nanosheets is of high interest owing to their promise for applications in electronics, filtration, catalysis, and chemical sensing. Using a facile approach inspired by biomineralization in nature, we fabricate laterally macroscopic calcium oxalate nanosheets using beta-folded peptides. The template...
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We report the synthesis of high-performance organic–inorganic hybrid fluorescent nanocapsules comprising a polymer shell armored with an inorganic layer and a liquid core containing a fluorophore. The polymeric capsules are synthesized by free radical miniemulsion polymerization and contain covalently bound carboxylate surface functionalities that...
Article
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L’estudi de la neologia és important no sols des d’un punt de vista metalingüístic, sinó també des de la perspectiva de la planificació lingüística, ja que mitjançant la monitorització de la creació lèxica és possible fer noves propostes lexicogràfiques i terminològiques. Donada la singularitat d’Andorra dins del domini lingüístic català, tant en t...
Article
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We demonstrate that the efficiency under ambient conditions of optically active molecules encapsulated in polymer nanocapsules can be significantly improved by depositing an inorganic layer onto the polymeric shell. A triplet‐triplet annihilation upconversion (TTA‐UC) system consisting of a porphyrin derivative and perylene is used as a representat...
Article
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The preparation and characterization of a porous hybrid cryogel based on the two organic polymers, poly(vinyl alcohol) (PVA) and karaya gum (KG), into which polyphosphate (polyP) nanoparticles have been incorporated, are described. The PVA/KG cryogel is prepared by intermolecular cross‐linking of PVA via freeze‐thawing and Ca²⁺‐mediated ionic gelat...
Article
The synthesis of conducting polymer nanoparticles by oxidative polymerization can be a challenge, because the addition of oxidizers may compromise the colloidal stability of the system. In this work, we report the successful synthesis poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles by means of miniemulsion polymerization. We study the role o...
Article
Nanodroplets in inverse miniemulsions provide a colloidal confinement for the crystallization of ammonium phosphomolybdate, influencing the resulting particle size. The effects of the space confinement are investigated by comparing the crystallization of analogous materials both in miniemulsion and in bulk solution. Both routes result in particles...
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Tuning sensing capabilities of simple to complex oxides for achieving enhanced sensitivity and selectivity toward the detection of toxic volatile organic compounds (VOCs) is extremely important and remains a challenge. In the present work, we report the synthesis of pristine and Ce-doped CuO hollow nanostructures, which have much higher VOC sensing...
Article
Inorganic polyphosphate [polyP] has proven to be a promising physiological biopolymer for potential use in regenerative medicine because of its morphogenetic activity and function as an extracellular energy‐donating system. Amorphous Ca²⁺–polyP nanoparticles [Ca–polyP‐NPs] are characterized by a high zeta potential with −34 mV (at pH 7.4). This sho...
Article
Given the great demand for polymers prepared from renewable materials, the synthesis of a glutamic-acid-based hydrogel by solution and inverse miniemulsion polymerization is herein presented. Free radical initiated homopolymerizations of N-acryloyl-L-glutamic acid (L-AGA) resulted in either a readily water-soluble polymer or a physically cross-link...
Chapter
Nanodroplets of a liquid in another immiscible liquid provide confined spaces in which chemical reactions can take place. If these reactions lead to the formation of nanoparticles, as it is the case for polymerization or precipitation reactions, nanodroplets can be used as templates for particle synthesis. The most common example of application of...
Article
Proteins can control mineralization of CaCO3 by selectively triggering the growth of calcite, aragonite or vaterite phases. The templating of CaCO3 by proteins must occur predominantly at the protein/CaCO3 interface, yet molecular-level insights into the interface during active mineralization have been lacking. Here, we investigate the role of pept...
Article
Magnetic resonance imaging has become an essential tool in medicine for the investigation of physiological processes. The key issues related to contrast agents, i.e., substances that are injected in the body for imaging, are the efficient enhancement of contrast, their low toxicity, and their defined biodistribution. Polyurea nanocapsules containin...
Article
Full-text available
Using femur explants from mice as an in vitro model, we investigated the effect of the physiological polymer, inorganic polyphosphate (polyP), on differentiation of the cells of the bone marrow in their natural microenvironment into the osteogenic and chondrogenic lineages. In the form of amorphous Ca-polyP nano/microparticles, polyP retains its fu...
Article
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In this study, the effect of inorganic polyphosphate (polyP) on the initial phase of angiogenesis and vascularization was investigated, applying the HUVEC cell tube formation assay. PolyP is a physiological and high energy phosphate polymer which has been proposed to act as a metabolic fuel in the extracellular space with only a comparably low ATP...
Article
Stable suspensions of chitosan nanoparticles were produced by the inverse miniemulsion technique and used as substrates for the crystallization of various polymorphs of calcium carbonate (CaCO3). These bioinspired chitosan nanoparticles were cross-linked with 1,4-butanediol diglycidyl ether, had an average particle diameter of 100–350 nm, and displ...
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Morbus Alzheimer neuropathology is characterized by an impaired energy homeostasis of brain tissue. We present an approach towards a potential therapy of Alzheimer disease based on the high-energy polymer inorganic polyphosphate (polyP), which physiologically occurs both in the extracellular and in the intracellular space. Rat pheochromocytoma (PC)...
Article
We present the design of multicompartment metal oxide/silica nanofibrous photocatalysts by colloid-electrospinning and subsequent calcination. During the calcination process, silica nanomaterials are cemented to form the fibrous framework and metal oxide precursors are crystallized inside and onto the fibers. This multicompartment nanofibrous struc...
Article
Photoactivated free radical miniemulsion copolymerization of methyl methacrylate (MMA) and the zirconium oxocluster Zr4O2(methacrylate)12 is used as an effective and fast preparation method of polymer/inorganic hybrid nanoparticles. The oxoclusters, covalently anchored to the polymer network, act as metal-organic cross-linkers, thus improving the t...
Article
Permeability is the key property of nanocapsules because it dictates the release rate of encapsulated payloads. Herein, we engineer the crystallinity of polymers confined in the shell of nanocapsules. Nanocapsules with crystalline shells are formed from polyurea and polyphosphoester. The thermal properties, such as crystallization temperature and d...
Article
Silica nanocapsules with various degrees of surface hydrophobicity were produced by using the inverse miniemulsion technique. Tetraethylorthosilicate was added concurrently with organosilanes containing a variety of hydrophobic ligands (e.g., cyclohexyl and octadecyl). The method is simple and yields nanosized capsules capable of containing hydroph...
Article
The paper discusses a successful strategy for tuning the hollow, porous or even solid morphologies of pure and Cu(2+)-doped CeO2 nanostructures. The reaction of nanodroplets at the interface in miniemulsions is significantly affected by the concentration of dopants. The growth mechanism is both reaction- as well as diffusion-controlled, which final...
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Crystalline first row transition metal (Mn, Fe, Co, Ni, Cu and Zn) ferrites were prepared by an unprecedented synerget-ic combination of miniemulsion synthesis and solvothermal route, pursuing unconventional conditions in terms of space confinement, temperature and pressure. This synergy allowed for obtaining six different crystalline ferrites at m...
Article
A heterophase method to prepare hollow and/or porous crystalline nanoparticles of metal oxides at room temperature is presented, taking cerium(IV) oxide and -iron(III) oxide (i.e., maghemite) as representative cases. The crystallization begins at the oil/water interface in aqueous nanodroplets of the precursor in inverse (water-in-oil) miniemulsio...
Article
Organic-inorganic hybrid nanoparticles are prepared by free-radical copolymerization of methyl methacrylate (MMA) with the structurally well-defined methacrylate-functionalized zirconium oxocluster Zr4O2(methacrylate)12. The polymerization process occurs in the confined space of miniemulsion droplets. The formation of covalent chemical bonds betwee...
Article
Giving the imminent necessity of a new generation of biodegradable and biocompatible polymers prepared from feedstock, the synthesis of a potentially biodegradable amino acid-based copolymer by the alternating diene metathesis (ALTMET) strategy is herein presented. The reaction was tailored to minimize isomerization and deactivation of ruthenium ca...
Cover Page
Front Cover: Amino-acid-based surfactants with polymer-izable moieties are used for the preparation of polymer nanoparticles with a chiral surface functionality. As an example of their application, the resulting chiral particles are shown to drive enantioselective crystallization of amino acid conglomerate systems. The cover image represents a chir...
Article
Amino-acid-based chiral surfactants with polymerizable moieties are synthesized, and a versatile approach to prepare particles thereof with a chiral surface functionality is presented. As an example of an application, the synthesized particles are tested for their ability as nucleating agents in the enantioselective crystallization of amino acid co...
Article
We compare the use of different trimethoxysilane compounds for the surface functionalization of magnetite nanoparticles and their subsequent incorporation in hybrid particles formed by in situ polymerization. For the encapsulation of inorganic nanoparticles via miniemulsion polymerization, surface functionalization of the inorganic material is nece...
Article
Silica nanoparticles are versatile materials whose physicochemical surface properties can be precisely adjusted. Because it is possible to combine several functionalities in a single carrier, silica-based materials are excellent candidates for biomedical applications. However, the functionality of the nanoparticles can get lost upon exposure to bio...
Article
The paper reports the crucial role of the morphology of poly(3,4-ethylenedioxythiophene) (PEDOT) nanostructures on the thermal and dielectric properties of polymer blends prepared thereof. PEDOT nanostructures with two different morphologies (nanoparticles and nanowires) were synthesized. The size for the nanoparticles was in the range 10-40 nm and...
Article
Full-text available
We report the synthesis of copper(ii) oxide hollow nanostructures at ambient pressure and close to room temperature by applying the soft templating effect provided by the confinement of droplets in miniemulsion systems. Particle growth can be explained by considering a mechanism that involves both diffusion and reaction control. The catalytic reduc...
Article
Statement of significance: Hydroxyapatite (HA) is a naturally occurring mineral of vertebrate bone. Natural HA, a bio-ceramic material which is crystalline to different scale, has been used as a biomaterial to fabricate scaffolds for in situ bone regeneration and other tissue engineering purposes. In contrast to natural HA, synthetic apatite is mu...
Article
Full-text available
Previous studies have reported that the metastable vaterite phase of calcium carbonate can be stabilized in solution by acidic additives. Here we demonstrate that vaterite can also be stabilized directly at surfaces by engineered peptides. Our data show that the mineralisation process occurs in a ‘self-templating’ process where calcium ions restruc...
Article
The structure control during the formation of films from nanoparticles is investigated. The particles are synthesized by miniemulsion polymerization with different ratios of methyl methacrylate and butyl methacrylate in the presence of silica nanoparticles. The structure of the hybrid particles is controlled by changing the surface properties of th...
Article
Full-text available
Chiral polymeric nanoparticles are of prime importance, mainly due to their enantioselective potential, for many applications such as catalysis and chiral separation in chromatography. In this article we report on the preparation of chiral polymeric nanoparticles by miniemulsion polymerization. In addition, we describe the use of isothermal titrati...
Article
Frontispiece: When triplet-triplet annihilation upconversion (TTA-UC) nanocapsules are synthesised at day light conditions and in the presence of molecular oxygen, the photo-induced oxidation of emitter molecules cannot be avoided. Only the synthesis at protective conditions warrants reproducible and sustainable upconversion results. Further detail...
Article
We have produced hybrid poly(urethane-urea)/silica nanocapsules with controlled molecular scale regimes of silica that break upon introduction into basic media. The miniemulsion technique used is simple and scalable, but yields complex molecular scale morphologies that create molecular gates for the release of hydrophilic components. The hybrid nan...
Article
We report the synthesis of ceria/polymer hybrid nanoparticles and their use as effective supported catalysts for the hydration of nitriles to amide, exemplified with the conversion of 2-cyanopiridine to 2-picolinamide. The polymeric cores, made of either polystyrene (PS) or poly(methyl methacrylate) (PMMA), are prepared by miniemulsion copolymeriza...
Chapter
Composite nanostructured particles can be produced by polymerization of monomer miniemulsion droplets loaded with inorganic nanoparticles. The article gives an overview on the development of a scalable continuous process for the production of such hybrid nanoparticles via miniemulsion polymerization. Different possibilities for the necessary surfac...