The Development of a Flexible Humidity Sensor Using MWCNT/PVA Thin Films.

The exponential demand for real-time monitoring applications has altered the course of sensor development, from sensor electronics miniaturization, e.g., resorting to printing techniques, to low-cost, flexible and functional wearable materials.

On the Fused Deposition Modelling of Personalised Bio-Scaffolds: Materials, Design, and Manufacturing Aspects.

Bone tissue engineering (BTE) is an important field of research, essential in order to heal bone defects or replace impaired tissues and organs. As one of the most used additive manufacturing processes, 3D printing can produce biostructures in the field of tissue engineering for bones, orthopaedic tissues, and organs. Scaffold manufacturing techniques and suitable materials with final structural, mechanical properties, and the biological response of the implanted biomaterials are an essential part of BTE.

Decoupling of Temperature and Strain Effects on Optical Fiber-Based Measurements of Thermomechanical Loaded Printed Circuit Board Assemblies.

This study investigated the use of distributed optical fiber sensing to measure temperature and strain during thermomechanical processes in printed circuit board (PCB) manufacturing. An optical fiber (OF) was bonded to a PCB for simultaneous measurement of temperature and strain. Optical frequency-domain reflectometry was used to interrogate the fiber optic sensor.

Graded Morphologies and the Performance of PffBT4T-2OD:PCBM Devices Using Additive Choice.

The impact of several solvent processing additives (1-chloronaphthalene, methylnaphthalene, hexadecane, 1-phenyloctane, and p-anisaldehyde), 3% / in o-dichlorobenzene, on the performance and morphology of poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2',5',22033,5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD):[6,6]-phenyl-C71-butyric acid methyl ester (PCBM)-based polymer solar cells was investigated. Some additives were shown to enhance the power conversion efficiency (PCE) by ~6%, while others decreased the PCE by ~17-25% and a subset of the additives tested completely eliminated any power conversion efficiency and the operation as a photovoltaic device. Grazing-Incidence Wide Angle X-ray Scattering (GIWAXS) revealed a clear stepwise variation in the crystallinity of the systems when changing the additive between the two extreme situations of maximum PCE (1-chloronaphthalene) and null PCE (hexadecane).

Operational Load Monitoring of a Composite Panel Using Artificial Neural Networks.

Operational Load Monitoring consists of the real-time reading and recording of the number and level of strains and stresses during load cycles withstood by a structure in its normal operating environment, in order to make more reliable predictions about its remaining lifetime in service. This is particularly important in aeronautical and aerospace industries, where it is very relevant to extend the components useful life without compromising flight safety. Sensors, like strain gauges, should be mounted on points of the structure where highest strains or stresses are expected.

Thiophene- and Carbazole-Substituted -Methyl-Fulleropyrrolidine Acceptors in PffBT4T-2OD Based Solar Cells.

The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2';5',2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) as donor and C or C fulleropyrrolidines as acceptors. The photovoltaic performance clearly depended on the molecular structure of the fulleropyrrolidine substituents although no direct correlation with the surface morphology of the photoactive layer, as determined by atomic force microscopy, could be established. Although some fulleropyrrolidines possess favorable lowest unoccupied molecular orbital levels, when compared to the standard PCBM, they originated OPV cells with inferior efficiencies than PCBM-based reference cells.

PffBT4T-2OD Based Solar Cells with Aryl-Substituted -Methyl-Fulleropyrrolidine Acceptors.

Novel C and C -methyl-fulleropyrrolidine derivatives, containing both electron withdrawing and electron donating substituent groups, were synthesized by the well-known Prato reaction. The corresponding highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels were determined by cyclic voltammetry, from the onset oxidation and reduction potentials, respectively. Some of the novel fullerenes have higher LUMO levels than the standards PCBM and PCBM.

A Comparative Study between Knocked-Down Aligned Carbon Nanotubes and Buckypaper-Based Strain Sensors.

Carbon nanotubes (CNTs) are one of the most promising materials in sensing applications due to their electrical and mechanical properties. This paper presents a comparative study between CNT Buckypaper (BP) and aligned CNT-based strain sensors. The Buckypapers were produced by vacuum filtration of commercial CNTs dispersed in two different solvents, N,N-Dimethylformamide (DMF) and ethanol, forming freestanding sheets, which were cut in 10 × 10 mm squares and transferred to polyimide (PI) films.

Carbonaceous Filler Type and Content Dependence of the Physical-Chemical and Electromechanical Properties of Thermoplastic Elastomer Polymer Composites.

Graphene, carbon nanotubes (CNT), and carbon nanofibers (CNF) are the most studied nanocarbonaceous fillers for polymer-based composite fabrication due to their excellent overall properties. The combination of thermoplastic elastomers with excellent mechanical properties (e.g.

Recent Developments in the Optimization of the Bulk Heterojunction Morphology of Polymer: Fullerene Solar Cells.

Organic photovoltaic (OPV) devices, made with semiconducting polymers, have recently attained a power conversion efficiency (PCE) over 14% in single junction cells and over 17% in tandem cells. These high performances, together with the suitability of the technology to inexpensive large-scale manufacture, over lightweight and flexible plastic substrates using roll-to-roll (R2R) processing, place the technology amongst the most promising for future harvesting of solar energy. Although OPVs using non-fullerene acceptors have recently outperformed their fullerene-based counterparts, the research in the development of new fullerenes and in the improvement of the bulk-heterojunction (BHJ) morphology and device efficiency of polymer:fullerene solar cells remains very active.

Development of porous lamellar poly(L-lactic acid) scaffolds by conventional injection molding process.

A novel fabrication technique is proposed for the preparation of unidirectionally oriented, porous scaffolds by selective polymer leaching from lamellar structures created by conventional injection molding. The proof of the concept is implemented using a 50/50 wt.% poly(L-lactic acid)/poly(ethylene oxide) (PLLA/PEO) blend.

Dynamic mechanical behavior of starch-based scaffolds in dry and physiologically simulated conditions: effect of porosity and pore size.

The three-dimensional scaffolds of a blend of starch and poly(L-lactic) acid, SPLA70, were produced using compression molding of polymer/salt mixture followed by leaching of salt. One series of scaffolds were prepared with varying polymer-to-salt ratio while keeping the salt size constant, and the other series of scaffolds were prepared with varying salt sizes while keeping the polymer-to-salt ratio constant. The X-ray microcomputed tomography and scanning electron microscopy assay were used to analyze the porous morphologies, porosity and distribution of porosity of the porous scaffolds.