Alberto García-Peñas

University Carlos III de Madrid | UC3M · Department of Materials Science and Engineering and Chemical Engineering

There has been an increase in interest with advanced photocatalytic materials due to the increasing importance of sustainable energy solutions and environmental remediation. BCN and BN-based materials have gained significant attention recently for their impressive electronic structures, exceptional chemical stability and interesting optical propert...

CIRMAT 2024 es un congreso científico y tecnológico sin ánimo de lucro multidisciplinar en que participan jóvenes universitarios, investigadores, y profesionales de algunas de las empresas más comprometidas con la transición de nuestro país. De una manera transversal abordaremos el reto que supone llevar la circularidad a nuestras vidas. Este congr...

Polysaccharide-based biopolymeric magnetic hydrogels have garnered significant attention as effective materials for wastewater treatment due to their high adsorption capacity and environmentally friendly nature. This review examines recent advancements in the development of biopolymeric magnetic hydrogels derived from polysaccharides such as cellul...

The increasing presence of antibiotics in aquatic ecosystems has raised serious concerns about their ecological and human health impacts. In response, extensive research has focused on the degradation and removal of these stubborn pollutants. Among various approaches, heterogeneous photocatalysis has gained prominence due to its effectiveness in el...

Smart polymers remain a compelling focus for researchers and industries due to their remarkable efficiency, adaptability, and specificity. These dynamic systems can react to external stimuli by altering their physicochemical properties, holding immense potential for a new wave of intelligent applications. The strategic functionalization of stimuli-...

Carbon materials, including carbon nanotubes/nanofibers, graphene, graphene oxide, reduced graphene oxide, graphyne, graphdiyne, carbon quantum dots and fullerenes, have received considerable attention in recent years because of their unique properties such as high conductivity, excellent stability and biocompatibility. The integration of these mat...

The present paper describes the design of shape-oriented hydrogel nanospheres using a facile ultrasonication-supported crosslinked copolymerization technique. The effect of variable monomer concentration on the homogeneity of hydrogel nanospheres was investigated. The chitosan-cl-poly(MMA) hydrogel nanospheres were well characterized using various...

A circular and environment-friendly economy could displace the linear economy as it is in use around the world. This would involve enlarged life cycles for products, and an increase in the efficiency of electric and electronic devices. The generation of new materials will be essential, as well as materials recycling or conversion after use. This bo...

The advances in terms of new materials used for CO2 collectors are growing due to the necessity to reduce the greenhouse gases emission and to respond to the environmental regulations. There are multiple systems which have shown remarkable properties for removal of specific pollutants. Nevertheless, the necessity of developing devices more effectiv...

The dramatic rise in carbon dioxide levels in the atmosphere caused by the continuous use of carbon fuels continues to have a significant impact on environmental degradation and the disappearance of energy reserves. Past few years have seen a significant increase in the interest in photocatalytic carbon dioxide reduction because of its ability to l...

Polypropylene-based thermoplastic elastomers continue to be materials of enormous industrial interest because of their high mechanical performance and durability. These materials are especially important, for instance, in the automotive industry, where these polyolefins accounts for up to 32% of the total plastic used in a car. In the search for ne...

In this study, nanocomposites based on polypropylene are synthesized by the in situ polymerization of propene in the presence of mesoporous SBA-15 silica, which acts as a carrier of the catalytic system (zirconocene as catalyst and methylaluminoxane as cocatalyst). The protocol for the immobilization and attainment of hybrid SBA-15 particles involv...

Hybrid hydrogels based on n-isopropylacrylamide, zwitterionic comonomer, and graphene oxide were synthesized to study their physical and mechanical properties. The compositional variation largely influenced the swelling characteristics of the hybrid hydrogels compared to mechanical properties, i.e., elongation and compression. Additionally, Rheomet...

Different circular strategies attempt to increase the energy efficiency or reduce the accumulation of plastic in landfills through the development of circular polymers. Chemical recycling is essential to recover the initial monomers from plastic residues for obtaining new goods showing the same properties as those using virgin monomers from the ini...

Libro de resúmenes del Simposio CIRMAT: Nuevos desarrollos para una economía circular. XX Jornada de Materiales celebrada en la Universidad Carlos III de Madrid el 24 de febrero de 2022. http://hdl.handle.net/10016/35645

The step-scheme (S-scheme) heterojunctions with superior redox capability have recently emerged as one of the most promising materials for cleaning up of contaminated environments. Herein, we synthesized g-C3N4/NiFe2O4 (NFC) heterojunction photocatalyst via a hydrothermal route for the degradation of Cephalexin (CPX). The integration of g-C3N4 and...

With a goal of waste-to-energy conversion, herein we report synchronous hydrogen evolution and pollutant degradation via photocatalysis utilizing novel Ni5P4/g-C3N4 S-scheme (Step scheme) heterojunction. The 25%Ni5P4/g-C3N4 (25NP/CN) sample generates 40.1 mmol g⁻¹ h⁻¹ hydrogen evolution and 94.4% carbamazepine degradation simultaneously under visib...

The use of polymers in biological applications is defined by the interactions promoted between living organisms and polymeric chains, which are generally associated with the polymers’ hydrophilic and hydrophobic behaviors. However, these water-friendly structures are also very useful for other applications, such as the adsorption of pollutants from...

In this Special Issue, several papers dedicated to biomedical, environmental, and biological applications have been assembled, representing different aspects of the field [...]

Correction for ‘Reactions of [60]fullerene with alkynes promoted by OH ⁻ ’ by Wei-Wei Chang et al. , RSC Adv. , 2022, 12 , 14018–14021. https://doi.org/10.1039/D2RA01300B.

In the current work, the reactions of [60]fullerene with alkynes promoted by OH− (base) are addressed. The treatment of C60 with alkynes in the presence of TBAOH produces alkynylation products (R-C60–H) with high selectivity in o-DCB at 100 °C. Plausible reaction mechanisms were proposed. This work provides a convenient and environmental friendly m...

New developments require innovative ecofriendly materials defined by their biocompatibility, biodegradability, and versatility. For that reason, the scientific society is focused on biopolymers such as chitosan, which is the second most abundant in the world after cellulose. These new materials should show good properties in terms of sustainability...

Herein, we report the designing of a C3N4/BiOI heterostructure that is supported on gum acacia-crosslinked-poly(acrylamide) hydrogel to fabricate a novel nanocomposite hydrogel. The potential application of the obtained nanocomposite hydrogel to remediate crystal violet dye (CVD) in an aqueous solution was explored. The structural and functional an...

To answer the question “How does lanthanide doping in iron oxide affect cure kinetics of epoxy-based nanocomposites?”, we synthesized samarium (Sm)-doped Fe3O4 nanoparticles electrochemically and characterized it using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM...

Designing and fabrication of smart hybrid multifunctional materials for energy/fuel production and environmental detoxification is indeed of great significance for sustainable development. Herein, we synthesized a new well-structured S-scheme heterostructure Fe@TiO2/Boron Carbon nitride (FT/BCN) with high performance tetracycline degradation and se...

The present research demonstrates the facile fabrication of xanthan gum-cl-poly(acrylamide-co-alginic acid) (XG-cl-poly(AAm-co-AA)) hydrogel by employing microwave-assisted copolymerization. Simultaneous copolymerization of acrylamide (AAm) and alginic acid (AA) onto xanthan gum (XG) was carried out. Different samples were fabricated by changing th...

There was a question on “how lanthanides doping in iron oxide affects cure kinetics of epoxy-based nanocomposites?” To answer, we synthesized samarium (Sm)-doped Fe3O4 nanoparticles via electrochemical method and characterized it using FTIR, XRD, FE-SEM, EDX, TEM, and XPS analyses. The magnetic particles were uniformly dispersed in epoxy resin to i...

The functionalization of smart polymers is opening a new perspective in catalysis, drug carriers and biosensors, due to the fact that they can modulate the response regarding conventional devices. This smart response could be affected by the presence of organometallic complexes in terms of interactions which could affect the physical chemical prope...

Many researchers are interested in investigating ceramic materials because of the potential for their use in nanotechnology. Spinel ferrites are a diverse group of materials with many applications. Electronic devices such as inductors, power, information storage, microwave, and induction tuners are only a few examples. As ferrite materials exhibit...

Hybrid hydrogel systems of functionalized MWCNTs and zwitterionic sulfobetaine copolymer of thermo-responsible Poly(N-Isopropylacrylamide) weresynthesized and testified against different existing diffusion kinetic models in neutral, acidic, and basic environments. Evaluating these hybrid hydrogels’ swelling patterns at different pH indicates that c...

Extensive research is being done to develop multifunctional advanced new materials for high performance photocatalytic applications in the field of energy production and environmental detoxification, MXenes have emerged as promising materials for enhancing photocatalytic performance owing to their excellent mechanical properties, appropriate Fermi...

Polylactic acid (PLA) is a semi-crystalline biopolymer with numerous applications in tissue engineering and regenerative medicine. PLA biodegradable devices are usually manufactured by extrusion or injection molding. The crystalline-amorphous structure that PLA acquires during processing is relevant for its applications as it determines the biodegr...

Recently, it was reported that the physical crosslinking exhibited by some biopolymers could provide multiple benefits to biomedical applications. In particular, grafting thermoresponsive polymers onto biopolymers may enhance the degradability or offer other features, as thermothickening behavior. Thus, different interactions will affect the differ...

The industry is looking for new materials which can respond to specific applications that exclusively advance materials can provide. In this context, nanoparticles and nanocomposites opened an interesting method for designing specific properties which can be modulated according to the requirements. The preparation of biomolecules supported trimetal...

The potential of bioresorbable metals to revolutionize current and future medical devices fascinates researchers. Magnesium, iron, and zinc have been thoroughly studied for the treatment of cardiovascular diseases or to repair fractures. Iron was the first type of metal being researched and introduced in biomedical applications. Magnesium is the mo...

This chapter is focused on some of the most important polymers used for preparing hybrid materials applied in biomedicine. The work is divided into two parts: Non-degradable polymers used for hybrid materials in implants and degradable polymers employed to fabricate biomedical implants and devices. Each part describes the main characteristics of th...

The book covers preparation, designing and utilization of nanohybrid materials for biomedical applications. These materials can improve the effectiveness of drugs, promote high cell growth in new scaffolds, and lead to biodegradable surgical sutures. The use of hybrid magneto-plasmonic nanoparticles may lead to non-invasive therapies. The most prom...

Recent advances focused on smart polymers have demonstrated the numerous advantages regarding other structures because they can adapt the behavior depending on physicochemical properties. In this way, functionalized thermoresponsive polymers with organometallic complexes were profoundly analyzed. Consequently, novel catalytic systems or biomedical...

Several copolymers based on propylene with 1‐nonene as comonomer have been synthesized within a wide range of compositions using a metallocene catalyst and different temperatures. The effect of the two main variables, comonomer content and polymerization temperature, on the final microstructure obtained (polymerization activity, stereochemistry and...

The combination of thermoresponsive polymers and biopolymers is growing due to the multiple benefits, owing to their tunable properties. Numerous works focus on the preparation of materials by chemical cross‐linking, but physical cross‐linking (based on hydrogen bonding) has not been deeply studied. In this context, questions around the hydrogen bo...

The functionalization of different structures with organometallic complexes provides exciting properties in terms of applicability due to its ability to provide multiple benefits for catalysis and biomedicine as well as in other fields. This work reports the direct, facile functionalization of copolymers based on N‐isopropylacrylamide and dopamine...

New materials tend to revolutionize scientific community and human race on a larger level. Scientists worldwide have not just been working on some wondrous materials with superior properties but have progressively focused on greener bio-inspired or bio-compatible materials for sustainable development. An increasing number of researchers have been w...

The effect of the molecular weight on the lower critical solution temperature (LCST) has been discussed extensively, where LCST increased with molar mass, decreased or kept constant, which leads to confusion. This work is focused on the preparation of poly(N‐isopropyl acrylamide) homopolymers, obtained in a wide molecular weights range. The LCST be...

The combination of thermoresponsive polymers with natural biomaterials can extend the properties portfolio, especially in the field of biomedicine, where a great cell adhesiveness and biodegradation is necessary for bone regeneration. The poly(N‐isopropylacrylamide)‐grafted‐gelatin gels were already reported where several synthetic parameters, such...

The “comonomer effect” is an intriguing kinetic phenomenon in olefin copolymerization that still remains without a detailed explanation. It typically relates to the rate of enhancement undergone in ethylene and propene catalytic polymerization just by adding small fractions of an alpha-olefin. The difficulty lies in the fact that changes caused by...

The development of multifunctional materials, specially nanocomposites, exhibit new and interesting properties which can extend the applicability ranges to diverse fields. In this way, the use of tri metallic nanoparticles, and derives, demonstrated higher efficacy for purification, catalytic activities and as antibacterial agents. This work is con...

For the preparation of thermoresponsive copolymers, for e.g., tissue engineering scaffolds or drug carriers, a precise control of the synthesis parameters to set the lower critical solution temperature (LCST) is required. However, the correlations between molecular parameters and LCST are partially unknown and, furthermore, LCST is defined as an ex...

Poly(N‐Isopropylacrylamide) has a broad potential range of biomedical applications owing to its lower critical solution temperature (LCST). This work tries to elucidate the real influence of several parameters on LCST by comparing homopolymers prepared by free radical polymerization and reversible addition–fragmentation chain transfer (RAFT) polyme...

The thermal stability of several isotactic polypropylenes and propylene‐co‐1‐nonene copolymers is assessed under nitrogen by means of thermogravimetric analysis (TGA). The samples involve wide ranges of molecular weight, isotactic average length, and 1‐nonene content, in order to perform a comprehensive analysis of the effect that chain features ex...

Natural biopolymers are better adsorbents due to better functionality, surface area, bio-compatibility and ease of procurement. The gum arabic in natural biopolymer derived from Acacia Arabic species. In the present work a novel nanohydrogel of gum arabic with acrylamide has been fabricated using microwave synthesis for adsorption of noxious crysta...

This work describes the important effects of microstructural features on crystalline structure, mechanical behavior and molten state response for poly (propylene-co-1-pentene-co-1-heptene) terpolymers. The study was carried out in a wide range of compositions, varying the 1-pentene/1-heptene ratio and the thermal history applied. Molecular features...

Room temperature positive magnetoresistance (PMR) in graphene is a conventional phenomenon but we observed large negative magnetoresistance (NMR) in GF/polydimethylsiloxane (GF/PDMS) at room temperature for the first time. The largest NMR ~ 35% was detected at 250 K, while positive magnetoresistance (PMR) is observed below 200 K. Furthermore, PMR a...

Nanocomposites based on polypropylene have been prepared by in situ polymerization of propene in presence of mesoporous SBA-15 silica. Synthetic reactions were carried out with a zirconocene catalyst under either homogenous or supported conditions, the SBA-15 particles being used as carriers, and testing the immobilization of the catalytic system b...

The influence of mesoporous SBA-15 on the thermal stability of nanocomposites with isotactic polypropylene has been evaluated in detail, both under inert and air conditions, by performing dynamic weight loss measurements and by tracking the evolution of degradation species in materials prepared by melt extrusion. A superior thermal stability has be...

A series of cytotoxic titanocene derivatives have been immobilized onto nanostructured silica-based materials using two different synthetic routes, namely, (i) a simple grafting protocol via protonolysis of the Ti–Cl bond; and (ii) a tethering method by elimination of ethanol using triethoxysilyl moieties of thiolato ligands attached to titanium. T...

A thorough evaluation of the mechanical behavior exhibited by fast crystallized propylene-1-pentene copolymers, synthesized in a broad range of 1-pentene compositions, is here described. Different mechanical magnitudes derived from loading, creep and unloading processes in depth sensing indentation measurements are correlated to structural features...

The mechanical response and crystalline structure have been analyzed in several propylene-co-1-pentene-co-1-hexene terpolymers. Different polymorphs are developed in these terpolymers depending on global comonomer content, 1-pentene:1-hexene ratio and thermal history. The trigonal δ crystal modification is observed in addition to monoclinic and ort...

The influence of the comonomer in the synthesis of poly(propylene-co−1-pentene) copolymers, with rac-(dimethylsilylbis(1-indenyl))ZrCl2/Methylaluminoxane at low temperature, has been studied. Changes in the catalyst activity and molecular weight have been analyzed as a function of copolymer composition, and associated with both content and nature o...

Different crystalline lattices are found to be developed in isotactic poly(propylene-co-1-pentene-co-1-hexene) terpolymers (synthesized by using a metallocene catalytic system) depending on: (a) overall content in comonomers, (b) 1-pentene/1-hexene ratio, and (c) crystallization and recrystallization conditions. The various polymorphs (monoclinic,...

Terpolymers based on propylene with 1-pentene and 1-heptene as comonomeric units are satisfactorily synthesized containing distinct overall compositions in comonomers as well as three different 1-pentene/1-heptene ratios at a given global composition. The effect of total content in counits and ratio between comonomers on polymerization activity, in...

The main results related to the mesophase formation in the different isotactic polypropylene (iPP) copolymers are reviewed in this chapter. It is shown that fast scanning calorimetry (FSC) is mandatory for analyzing the process at the lower comonomer contents. On the contrary, the cooling rates required for the relatively high contents fall in the...

The role played by mesophases in the ordering of polymers, namely if they are either competitors with the more stable crystal structures, or they act as precursors of subsequent crystallization, has been analyzed in two kinds of systems: a) isotactic polypropylene and copolymers with 1-pentene, as representative of forming solid mesophases, and b)...

A sample of isotactic poly-1-pentene has been synthesized by using a metallocene catalyst, and two specimens have been prepared displaying the most stable Form I of this polymer, reported to adopt a 31 helical conformation. The solid-state 13C-NMR study of this helical form shows an exceptional splitting of the resonances, indicative of an importan...

The influence of crystallization rate on the interesting polymorphism of random isotactic poly(propylene-co-1-heptene) copolymers has been studied, with a particular attention to the conditions for obtaining the mesomorphic phase. Owing to the important decrease of cooling rates involved as 1-heptene content increases, the mesophase can be clearly...

Poly(propylene-co-1-heptene) copolymers have been evaluated in a wide 1-heptene content range. Two different polymorphs can be observed in this interval under the processing conditions imposed: monoclinic crystallites and mesomorphic entities. The unique presence of one or the other lattice at specific contents or the coexistence of both of them at...

Two series of propylene based copolymers with 1-pentene and 1-hexene, respectively, have been synthesized via metallocene catalysis up to comonomer contents around 14 mol %. The pyrolysis behavior of these propylene-rich copolymers has been studied and compared with the corresponding thermal response of the referential isotactic polypropylene (iPP)...

Isotactic polypropylene can be found in an enormous variety of applications, and, consequently, its demand is extraordinary high between those polymers denominated as “commodities”. Requirements of markets joined to expansion of its uses and new environmental policies, among others factors, are underneath the numerous efforts that are being carried...

Different polymorphs are developed in isotactic poly(propylene-co-1-heptene) copolymers depending on 1-heptene molar content and thermal history: monoclinic and orthorhombic crystallites as well as mesomorphic entities. Indentation hardness values and deformability are found to be related to those variables as well as to crystallinity degree. Conse...

This study aims at characterizing in depth the microstructure of propylene-co-1-pentene-co-1-hexene terpolymers, which have been recently reported to develop the isotactic polypropylene δ trigonal polymorph when the total comonomer content is high enough. Such a specific crystalline form had been only reported so far in the analogous copolymers con...

Terpolymers based on propylene with 1-pentene and 1-hexene as comonomeric units are satisfactorily synthesized using a metallocene catalyst. Thus, several terpolymers are prepared with distinct overall compositions in comonomers as well as three different 1-pentene/1-hexene ratios at a given composition to evaluate the influence on polymerization a...

Titanocene dichloride [Ti(η(5)-C(5)H(5))(2)Cl(2)] (1), has been grafted onto dehydrated hydroxyapatite (HAP), Al(2)O(3) and two mesoporous silicas MSU-2 (Michigan State University Silica type 2) and HMS (Hexagonal Mesoporous Silica), to give the novel materials HAP/[Ti(η(5)-C(5)H(5))(2)Cl(2)] (S1) (1.01 wt.% Ti), Al(2)O(3)/[Ti(η(5)-C(5)H(5))(2)Cl(2...