Browsing by Author "Perez, Yasmin P."

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    New Hybrid Copper Nanoparticles/Conjugated Polyelectrolyte Composite with Antibacterial Activity
    (2021) Jessop, Ignacio A.; Perez, Yasmin P.; Jachura, Andrea; Nunez, Hipolito; Saldias, Cesar; Isaacs, Mauricio; Tundidor-Camba, Alain; Terraza, Claudio A.; Araya-Duran, Ingrid; Camarada, Maria B.; Carcamo-Vega, Jose J.
    In the search for new materials to fight against antibiotic-resistant bacteria, a hybrid composite from metallic copper nanoparticles (CuNPs) and a novel cationic pi-conjugated polyelectrolyte (CPE) were designed, synthesized, and characterized. The CuNPs were prepared by chemical reduction in the presence of CPE, which acts as a stabilizing agent. Spectroscopic analysis and electron microscopy showed the distinctive band of the metallic CuNP surface plasmon and their random distribution on the CPE laminar surface, respectively. Theoretical calculations on CuNP/CPE deposits suggest that the interaction between both materials occurs through polyelectrolyte side chains, with a small contribution of its backbone electron density. The CuNP/CPE composite showed antibacterial activity against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria, mainly attributed to the CuNPs' effect and, to a lesser extent, to the cationic CPE.
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    New polyimides containing methyl benzamidobenzoate or dimethyl benzamidoisophthalate as bulky pendant groups. Effects on solubility, thermal and gas transport properties
    (2022) Terraza, Claudio A.; Cruz, Yennier; Rodriguez, Ary; Victoria Velazquez-Tundidor, Maria; Hauyon, Rene A.; Rodriguez-Gonzalez, Fidel E.; Niebla, Vladimir; Aguilar-Vega, Manuel; Sulub-Sulub, Rita; Coll, Deysma; Ortiz, Pablo A.; Perez, Yasmin P.; Comesana-Gandara, Bibiana; Tundidor-Camba, Alain
    This work reports the synthesis of six new polyimides obtained by the reaction of two novel diamine monomers: methyl 4-(3,5-diaminobenzamido)benzoate and dimethyl 5-(3,5-diaminobenzamido)isophthalate, bearing one or two methyl ester groups in their phenyl rings, respectively, with three known dianhydrides, 4,4 '-(hexafluoroisopropylidene) diphatalic anhydride (6FDA), 4,4 '-(dimethylsilanediyl) dipthalic anhydride (SiDA) and 4,4 '-oxydiphthalic anhydride (ODPA). The polyimides were synthesized using the "two-step" method, which first involves forming a poly(amic acid) precursor that is subsequently cyclodehydrated to form the imide linkage. The yields were higher than 95% in all cases, and the structural characterization was performed by spectroscopic techniques like FT-IR, H-1, C-13, and Si-29 NMR. In addition, the effect on the solubility in common organic solvents and thermal and gas transport properties of these polyimides were studied as a function of the nature of the respective side group and the dianhydride used.