8 documents found, page 1 of 1
Poly(lactic acid) composites with few layer graphene produced by noncovalent ch...
Peixoto, Tânia; Nunes, Joana; Lopes, Maria A.; Marinho, Elina Margarida Ribeiro; Proença, M. Fernanda R. P.; Lopes, Paulo Estevão CaldeiraIn recent years, significant attention has been given to “green” product innovation and related manufacturing processes. This work reports the preparation of few-layer graphene (FLG) and respective PLA-based composites by an ecofriendly, efficient, and cost-effective approach. FLG was produced in a scaledup process, based on the noncovalent functionalization of a micronized graphite with a pyrene derivate (PY),...
Self-assembly of Boc-p-nitro-l-phenylalanyl-p-nitro-l-phenylalanine and Boc-l-p...
Baptista, Rosa Maria Ferreira; Lopes, Paulo Estevão Caldeira; Rodrigues, Ana Rita O.; Cerca, Nuno; Belsley, M.; de Matos Gomes, EtelvinaSelf-assembly of two N-tert-butoxycarbonyl (Boc) protected analogues of diphenylalanine dipeptide, Boc-p-nitro-l-phenylalanyl-p-nitro-l-phenylalanine and Boc-l-phenylalanyl-l-tyrosine, respectively, Boc-pNPhepNPhe and Boc-PheTyr, in 1,1,1,3,3,3-hexafluoro-2-propanol/ethanol(water) solvents and into electrospun fibers is studied. Uncommon dual self-assembly is found for Boc-pNPhepNPhe, with the formation of nano...
Polylactic acid/carbon nanoparticle composite filaments for sensing
Silva, Mariana M.; Lopes, Paulo Estevão Caldeira; Li, Yilong; Pötschke, Petra; Ferreira, Fernando; Paiva, M. C.Polylactic acid (PLA) is a bio-based, biodegradable polymer that presents high potential for biomedical and sensing applications. Ongoing works reported in the literature concern mainly applications based on 3D printing, while textile applications are hindered by the limited flexibility of PLA and its composite filaments. In the present work, PLA/multiwall carbon nanotube (MWCNT) composite filaments were produc...
Anisotropic PCL nanofibers embedded with nonlinear nanocrystals as strong gener...
Bernardo, Cesar R.; Baptista, Rosa M. F.; de Matos Gomes, Etelvina; Lopes, Paulo Estevão Caldeira; Raposo, M. Manuela M.; Costa, Susana P. G.Using the electrospinning technique nanofibers consisting of organic nonlinear optical 3-nitroaniline (3NA, C6H6N2O2) nanocrystals embedded in poly-ε-caprolactone (PCL) polymer, 3NA@PCL nanofibers, were produced. Polarimetry optical second harmonic generation and X-ray diffraction studies show that 3NA push–pull molecules crystallize inside the polymer fibers with a strong preferential orientation giving rise t...
Mixed carbon nanomaterial/epoxy resin for electrically conductive adhesives
Lopes, Paulo Estevão Caldeira; Moura, Duarte; Hilliou, L.; Krause, Beate; Pötschke, Petra; Figueiredo, Hugo; Alves, Ricardo; Lepleux, EmmanuelThe increasing complexity of printed circuit boards (PCBs) due to miniaturization, increased the density of electronic components, and demanding thermal management during the assembly triggered the research of innovative solder pastes and electrically conductive adhesives (ECAs). Current commercial ECAs are typically based on epoxy matrices with a high load (>60%) of silver particles, generally in the form of m...
Advanced electrically conductive adhesives for high complexity PCB assembly
Lopes, Paulo Estevão Caldeira; Moura, Duarte Alexandre Campos Serra; Freitas, D.; Proença, M. Fernanda R. P.; Figueiredo, H.; Alves, R.; Paiva, M. C.Electronic packaging, or assembly of packed electronic components on printed circuit boards, present challenges that require innovative solder pastes and electrically conductive adhesives to face the increasing complexity of PCB assembly, with denser board occupation and demanding thermal management during assembly. Our aim is to prepare carbon particle based conductive adhesives. The first step to achieve this...
Self-assembly of dipeptide Boc-diphenylalanine nanotubes inside electrospun pol...
Baptista, Rosa M. F.; Gomes, Etelvina de Matos; Raposo, M. Manuela M.; Costa, Susana P. G.; Lopes, Paulo Estevão Caldeira; Almeida, B. G.; Belsley, M.Dipeptide biomaterials are strong piezoelectric materials that can convert applied mechanical forces into electricity. We have developed large-scale hybrid electrospun arrays containing N-tert-butoxycarbonyl (Boc) diphenylalanine in the form of nanotubes embedded in biocompatible polymers. These nanofibers exhibit strong piezoelectric properties when a periodic mechanical force is applied. The nanostructured hy...
Production of cellulose nanofibers from Alfa grass and application as reinforce...
Ben Cheikh, Salma; Ben Cheikh, Ridha; Cunha, Eunice Paula Freitas; Lopes, Paulo Estevão Caldeira; Paiva, M. C.The work reported demonstrates an simple method of extracting cellulose nanofibers (CNF) from cellulose microfibers (CMF) obtained from the plant Stipatenacissima. Here, a method for the production of CNF from CMF extracted from Alfa grass by exfoliation in polyvinyl alcohol (PVA) solution, is demonstrated. The CMF were produced in powder form and exfoliated in PVA aqueous solution to produce composites with 2,...