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In this work, the modification of ethylene-co-vinyl alcohol (EVOH) copolymer with a coumarin derivative, 7- (hydroxyethoxy)-4-methyl coumarin (HEOMC), has been performed through the incorporation of different reactive groups, p-nitrophenyl chloroformate, succinic anhydride and phthalic anhydride as different linkers between coumarin and EVOH with the aim to obtain photo-responsive materials with improved protein absorption resistance. After purification, the modification degree was calculated by nuclear magnetic resonance and ultraviolet- visible spectroscopy. The thermal properties revealed the crystallinity loss and higher maximum degradation temperatures when EVOH is modified with coumarin derivative. Copolymers were successfully photocrosslinked through the photo-responsive behavior of coumarin moieties. The micro-hardness test shown an increase of the mechanical performance due to the coumarin presence. The water contact angle measurements revealed that while coumarin-modified EVOH copolymers present a higher hydrophilic behavior than EVOH, the photo-dimerization process mainly leads to slightly deviations on the surface wettability of neat EVOH. Finally, the absorption of bovine serum albumin onto the surface of the coumarin-modified materials revealed enhanced antifouling properties, particularly after the photo-crosslinked process. Therefore, the introduction of coumarin through different chain extenders leads to functional materials with tunable photo-responsive performance and protein absorption resistance., Authors thank Spanish Ministry of Science and Innovation (Projects MAT2016-78437-R MAT2017-88123-P), the Agencia Estatal de Investigación (AEI, Spain) and Fondo Europeo de Desarrollo Regional (FEDER, EU). M.P.A. and L.P. acknowledge the Juan de la Cierva (FJCI- 2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINECO, respectively. A.C. also acknowledges his FPU fellowship FPU18/01776.

7th International Conference on Biobased and Biodegradable Polymers (BIOPOL). Stockholm, SWEDEN, JUN 17-19, 2019, Smart and functional properties of coumarin and PCL-based polyurethane (PU) nanocomposites reinforced with both pristine silica nanoparticles and silica nanoparticles modified with coumarin, have been studied. Coumarin is a photo-responsive derivative, which induces photo-crosslinking when it is incorporated in the PU moieties. Swelling measurements were performed to study the photo-crosslinking fraction and the results are in concordance with the degree of crosslinking (DC) calculated by UV measurements. Shape memory behavior was studied by thermo-mechanical cycles, by measuring the strain recovery and shape fixity ratios of the photo-crosslinked films. The modification of silica nanoparticles allows an improvement in the dispersion of the reinforcements into the PU matrix, which leads to an enhancement of the shape memory properties. Finally, the materials were disintegrated under composting conditions at laboratory scale level to confirm their biodisintegrable behavior.

Photo-reversible nanocomposites of polyurethanes (PUs) based on coumarin (CD) and poly(e-caprolactone) (PCL), with different molecular weights (PCL530, PCL2000) were developed. High molecular weight PUs were loaded with three different amounts of fumed silica nanoparticles (SiNPs) (1, 3 and 5 wt%) to improve their physical, mechanical, thermal and photo-chemical properties. The incorporation of SiNPs and the interaction with the PU matrix was confirmed by FTIR, while their dispersion was observed by Field Emission Scanning Electron Microscopy (FE-SEM). The thermal stability of PU nanocomposites was improved due to the positive interaction of SiNPs with PU matrix. The incorporation of SiNPs leads to the formation of more thermal stable semicrystalline structure. Stress-strain experiments showed an increase on Young‘s modulus. Surprisingly, the photo-reversible ability of nanocomposites measured by UV–vis exhibited faster photo-dimerization process in PCL2000-PUs based nanocomposites than in PCL530-PUs ones, contrarily to the behavior of PUs without SiNPs. These nanocomposites are promising systems to design versatile and sustainable coatings with improved thermal stability and tunable mechanical performance.

Amphiphilic nonionic ligands, synthesized with a fixed hydrophobic moiety formed by a thiolated alkyl chain and an aromatic ring, and with a hydrophilic tail composed of a variable number of oxyethylene units, were used to functionalize spherical gold nanoparticles (AuNPs) in water. Steady-state and time-resolved fluorescence measurements of the AuNPs in the presence of α-cyclodextrin (α-CD) revealed the formation of supramolecular complexes between the ligand and macrocycle at the surface of the nanocrystals. The addition of α-CD induced the formation of inclusion complexes with a high apparent binding constant that decreased with the increasing oxyethylene chain length. The formation of polyrotaxanes at the surface of AuNPs, in which many α-CDs are trapped as hosts on the long and linear ligands, was demonstrated by the formation of large and homogeneous arrays of self-assembled AuNPs with hexagonal close packing, where the interparticle distance increased with the length of the oxyethylene chain. The estimated number of α-CDs per polyrotaxane suggests a high rigidization of the ligand upon complexation, allowing for nearly perfect control of the interparticle distance in the arrays. This degree of supramolecular control was extended to arrays formed by AuNPs stabilized with polyethylene glycol and even to binary arrays. Electromagnetic simulations showed that the enhancement and distribution of the electric field can be finely controlled in these plasmonic arrays., This work was funded by the Spanish MINECO (MAT2014-59678-R and CTQ2015-65972-R), and the Madrid Regional Government (S2013/MIT-2807). A.G.-M. and S.G.-G. acknowledge receipt of a “Ramón y Cajal” and “Juan de la Cierva” fellowships, respectively, from the Spanish MINECO. P.D.N. acknowledges DIMMAT project funded by the Madrid Regional Government (S2013/MIT-2775). The authors acknowledge the facilities provided by the Nuclear Magnetic Resonance Center and the National Center of Microscopy (Universidad Complutense de Madrid).

Coumarin and poly-ε-(caprolactone) diol (PCL)-based polyurethanes (PUs), were reinforced with modified silica nanoparticles (mSiNPs), in which a novel coumarin molecule was synthetized. The behavior as photo-responsive coatings of these materials was studied. The silica nanoparticles (SiNPs) modification was analyzed by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and UV spectroscopy. The yield of photo-crosslinking in nanocomposites loaded with mSiNPs was studied by UV–vis spectroscopy, which showed higher conversion degree than nanocomposites with unmodified SiNPs and non-reinforced PUs. The dispersion of mSiNPs on segregated microdomains was observed by transmission electron microscopy (TEM). The presence of coumarin grafted on the SiNPs surface (mSiNPs) leads to an improvement on the thermal stability of PU matrix. Meanwhile, they were able to maintain the mechanical performance before and after the irradiation process mainly due to the improved nanofiller-matrix interaction. Contact angle measurements were also assayed to study the hydrophobicity changes on the surface of modified nanocomposites. The observed phase segregation was associated with the mechanical and thermal properties of the materials and the photo-crosslinking of coumarin moieties bring to the final material high responsiveness to be employed as photo-switchable coatings., Authors thank Spanish Ministry of Economy, Industry and Competitiveness, MINEICO (MAT2013-48059-C2-1-R) and Regional Government of Madrid (S2013/MIT-2862). M.P.A. and L.P. acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC- 2014-15595) contracts from the MINEICO, respectively. Authors specially thank Dr. Emilio Rayón and Prof. Juan López Martínez (Universitat Politècnica de València, Spain) for TEM analysis

Enzymatic polymerization has a large potential as an environmentally friendly synthetic process. Lipase is a renewable catalyst with high catalytic activity from which it is possible to develop a versatile method for the production of sustainable polyurethanes. In this work oligomeric PCL-diol was synthesized using biocatalysis with immobilized Yarrowia lipolytica lipase (YLL) and diethyleneglycol as initiator. Then, two different linear polyurethanes were prepared. One was obtained directly from the previous synthesized PCL-diol and hexamethylene diisocyanate, named PU, and the other one has been obtained by incorporating L-lysine amino acid as end group (lys-PU). PU and lys-PU disintegration under composting conditions was evaluated. The influence of the presence of L-lysine on the disintegration performance of PU was studied by evaluating the disintegration degree, monitoring the weight loss. Structural and morphological changes were followed by Fourier transformed infrared spectroscopy (FTIR) and by scanning electron microscopy (SEM)., Authors thank Spanish Ministry of Economy, Industry and Competitiveness, MINEICO, ( and MAT2013-48059-C2-1-R MAT2017-88123-P) cofinanced with FEDER funds, Regional Government of Madrid (S2013/MIT-2862) and Consejo Nacional de Ciencia y Tecnología (CONACYT, Grant 153922) for the financial support. M.P. Arrieta and L. Peponi acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINECO, respectively. Authors also acknowledge Prof. Juan López Martínez (Universitat Politécnica de Valencia, Spain) for his assistance with colorimetric measurements.

A synthesized thiol-functionalized non-ionic surfactant based on the IGEPAL® (polyoxyethylene(5) nonyl phenyl ether) structure, has been used to replace citrate ions from the surface of gold nanoparticles with 13.5 nm diameters. Upon IGEPAL®-type stabilization in water, the nanoparticles were transferred to ethanol, where a layer of silica was efficiently grown on the nanocrystal surface through the conventional Stober approach. This method allows fine control over the silica thickness, showing uniform and homogeneous core-shell nanoparticles. Additionally, the luminescent properties of the IGEPAL® surfactant allow the versatile preparation of robust fluorescent nanoparticles with multiplexing potential as simultaneous plasmonic and fluorescence probes.

The use of a thiol-functionalized nonionic surfactant to stabilize spherical gold nanoparticles in water induces the spontaneous formation of polyrotaxanes at the nanoparticle surface in the presence of the macrocycle α-cyclodextrin. Whereas using an excess of surfactant an amorphous gold nanocomposite is obtained, under controlled drying conditions the self-assembly between the surface supramolecules provides large and homogenous supercrystals with hexagonal close packing of nanoparticles. Once formed, the self-assembled supercrystals can be fully redispersed in water. The reversibility of the crystallization process may offer an excellent reusable material to prepare gold nanoparticle inks and optical sensors with the potential to be recovered after use.

Intermolecular and intramolecular halogen···π interactions in benzylic halides (Ph-CR2-X; X = F, Cl, Br and I) derived from 7-phenylnorbornane were investigated. The imposed geometry of the 7-arylnorbornane moiety prevents the participation of intramolecular attractive interactions between the σ-hole region of the halogen atom and the π electrons of the aromatic ring. Crystallographic data show intermolecular halogen bonds in iodide 1 and bromide 2 in the solid state. On the other hand, both UV-Vis and D-NMR data suggest the occurrence of intramolecular interactions between the halogen atoms and the phenyl rings in these compounds in solution. To provide more insight into the nature of the observed stabilizing interactions, density functional calculations were also carried out. These computations confirm the presence of genuine lone pairπ intramolecular interactions which strongly affect the stability and the electronic structure of these species.

Photo-reversible polyurethane (PU) coatings based on coumarin diol (CD) are obtained. Initially, pre-polymers based on different amounts of coumarin (5, 15, and 25 mol%) and 1,6-hexamethylene diisocyanate are prepared to obtain PUs with a large incorporation of CD and high molecular weight. The pre-polymer is posterior reacted with poly(ε-caprolactone) diol (PCL-diol), either with molecular weight (Formula presented.) = 530 or 2000 g mol. The thermal stabilities of the PUs are studied using thermogravimetric analysis. Polymers with a higher content of CD present higher stability. The thermal transitions and the mechanical response are analyzed using differential scanning calorimetry and strain-stress tests, respectively. Moreover, the photo-reversibility of CD-based PUs is followed by UV absorption. In general, photo-dimerization induces better mechanical properties of the final PUs. Materials obtained with short PCL-diol ((Formula presented.) = 530 g mol) and the highest amount of CD present higher reversibility processes. Therefore, these polymers are promising for application as coating systems. (Figure presented.)., Acknowledgements: The authors would like to thank the Spanish Ministry of Science and Innovation (MAT2013-48059-C2-1-R and MAT2014-55778-REDT) and the Regional Government of Madrid (S2013/MIT-2862). M.P.A. and L.P. acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINECO, respectively