Hydrophobic performance of electrospun fibers functionalized with TiO2 nanoparticles

2021 ◽  
pp. 004051752110106
Author(s):  
Vânia Pais ◽  
Miguel Navarro ◽  
Catarina Guise ◽  
Rui Martins ◽  
Raul Fangueiro
Keyword(s):  
Electron Microscopy ◽  
Polymer Concentration ◽  
Water Repellent ◽  
Scanning Calorimetry ◽  
Hydrophobic Properties ◽  
Water Contact ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Biodegradable Poly ◽  
Needle Diameter

The development of materials with hydrophobic properties has been widely explored in areas such as textiles, healthcare, sports, and personal protective equipment. Hydrophobic properties that arise from nanoparticles (nPs) directly promote other valuable properties, including self-cleaning capabilities, decreased bacterial growth, and increased comfort. In this study, biodegradable poly(ε-caprolactone) (PCL) nanofibers were functionalized by the incorporation of titanium dioxide (TiO2) nPs to develop water-repellent materials. The membranes were produced through electrospinning, and variables such as the polymer concentration, nP concentration, and needle diameter were optimized to achieve PCL/TiO2 composite fibers with water-repellent capabilities. The nanofibers were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, and the water contact angle (WCA). In general, it was observed that the nanofibers presented higher roughness values when TiO2 nPs were present and that this result promoted higher WCA values. The highest WCA value (156°) was obtained for the nanofiber mat produced with 20% weight-to-volume (w/v) PCL and 0.6% (w/v) TiO2.

Synthesis of polystyrene-grafted carbon nanocapsules

2007 ◽  
Vol 22 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Hsuan-Ming Huang ◽  
Hung-Chieh Tsai ◽  
I-Chun Liu ◽  
Raymond Chien-Chao Tsiang
Keyword(s):  
Electron Microscopy ◽  
Molecular Weight ◽  
Polymeric Composite ◽  
Decomposition Temperature ◽  
Polymeric Composite Material ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Carbon Nanocapsules

A novel polymeric composite material, polystyrene (PS)-grafted carbon nanocapsules (CNCs), has been prepared. sec-butyllithium was first used to introduce negative charges on CNCs, and these CNC carbanions acted then as initiators for anionic polymerization of styrene. Based on a weight loss at the decomposition temperature of the butyl groups, the quantity of the butyls attached to the CNC surface was determined as 1.18 wt%, corresponding to 0.25 mol% initiator per mol of carbon atom on the CNC surface. Furthermore, the decomposition temperature of butylated CNCs was lower than that of the pristine CNCs by nearly 200 °C. The polystyrene content in our PS-grafted CNC sample was approximately 20%, and the molecular weight of the grafted PS on the surface of CNCs was calculated as 1200 gmol−1. Compared with the molecular weight of the ungrafted PS, the molecular weight of grafted PS was lower, thus indicating rates of initiation and/or propagation for CNC-bound carbanions lower than those of the free sec-butyllithium. The PS-grafted CNCs had good dispersion in toluene, tetrahydrofuran, cyclohexane, and other common organic solvents in which polystyrene was dissolvable and thus indicated good compatibility when further blended with other styrenic polymers. The PS-grafted CNCs were characterized and examined by Fourier transform infrared, thermogravimetric analysis, atomic force microscopy, differential scanning calorimetry, ultraviolet-visible spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electron microscopy images indicated that the PS-grafted CNCs were homogeneous composites containing uniform polymer/CNC ratios.

scholarly journals Characterization of the Spindle Morphology Nanomicelles Assembled from Sericin and Gelatin

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Xiaozhou Su ◽  
Lei Li ◽  
Weihan Huang
Keyword(s):  
Electron Microscopy ◽  
Protein Concentration ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Storage ◽  
Ft Ir Spectroscopy

Complex nanomicelles were prepared by sericin and type A gelatin with molecular weight of 5789 Da and 128664 Da separately. The assembling conditions were as follows: mass ratio (sericin/gelatin) was 1 : 1, protein concentration was 0.5%, temperature was 35°C, and assembling time was 18 hours. Scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and dynamic light scattering (DLS) were conducted to observe and characterize the complex nanomicelles. Results showed that the complex sericin/gelatin micelles was a kind of nanospindle micelles. The micelles had high electrochemical stability, thermal stability, antidilution stability, and storage stability.

scholarly journals Hydrophobic Epoxy Caged Silsesquioxane Film (EP-POSS): Synthesis and Performance Characterization

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 472
Author(s):  
Yanhong Fang ◽  
Ping Wang ◽  
Lifang Sun ◽  
Linhong Wang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
Solar Panels ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Surface Micromorphology ◽  
And Performance

Hydrophobic films are widely used in aerospace, military weapons, high-rise building exterior glass, and non-destructive pipeline transportation due to their antifouling and self-cleaning properties. This paper details the successful preparation of hydrophobic epoxy caged sesquioxane (EP-POSS) via two steps of simple organic synthesis, along with studies on the effects of viscosity and reaction time on the reaction. Interestingly, the EP-POSS presented a large contact angle of 125°, indicating its excellent hydrophobicity. The surface micromorphology was observed via FE-SEM (field emission scanning electron microscopy), transmission electron microscopy (TEM), and atomic force microscopy (AFM), and the structural composition and elemental contents were analyzed via X-ray photoelectron spectroscopy (XPS) and energy-dispersive spectrometry (EDS). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) tests showed that EP-POSS had excellent thermal properties, and the first degradation reaction occurred at 354 °C. The mechanical performance and abrasion resistance results demonstrated that EP-POSS could be used in solar panels.

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

scholarly journals Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

Effectiveness and Reliability of Metal Diffusion Barriers for Copper Interconnects

1995 ◽  
Vol 403 ◽  
Author(s):  
G. Bai ◽  
S. Wittenbrock ◽  
V. Ochoa ◽  
R. Villasol ◽  
C. Chiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Chemical Vapor ◽  
Diffusion Barriers ◽  
Copper Interconnects ◽  
Time To Failure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

AbstractCu has two advantages over Al for sub-quarter micron interconnect application: (1) higher conductivity and (2) improved electromigration reliability. However, Cu diffuses quickly in SiO2and Si, and must be encapsulated. Polycrystalline films of Physical Vapor Deposition (PVD) Ta, W, Mo, TiN, and Metal-Organo Chemical Vapor Deposition (MOCVD) TiN and Ti-Si-N have been evaluated as Cu diffusion barriers using electrically biased-thermal-stressing tests. Barrier effectiveness of these thin films were correlated with their physical properties from Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Secondary Electron Microscopy (SEM), and Auger Electron Spectroscopy (AES) analysis. The barrier failure is dominated by “micro-defects” in the barrier film that serve as easy pathways for Cu diffusion. An ideal barrier system should be free of such micro-defects (e.g., amorphous Ti-Si-N and annealed Ta). The median-time-to-failure (MTTF) of a Ta barrier (30 nm) has been measured at different bias electrical fields and stressing temperatures, and the extrapolated MTTF of such a barrier is > 100 year at an operating condition of 200C and 0.1 MV/cm.

Development of Ge Nanoparticles Embedded in GeO2 Matrix

2008 ◽  
Vol 8 (8) ◽  
pp. 4081-4085 ◽  
Author(s):  
Y. Batra ◽  
D. Kabiraj ◽  
D. Kanjilal
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Spectroscopic Studies ◽  
Electron Beam Evaporation ◽  
Granular Structure ◽  
Raman Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Ge Nanocrystals

Germanium (Ge) nanoparticles have attracted a lot of attention due to their excellent optical properties. In this paper, we report on the formation of Ge nanoparticles embedded in GeO2 matrix prepared by electron beam evaporation and subsequent annealing. Transmission electron microscopy (TEM) studies clearly indicate the formation of Ge nanocrystals in the films annealed at 500 °C. Fourier transform infrared (FTIR) spectroscopic studies are carried out to verify the evolution of the structure after annealingat each stage. Micro-Raman analysis also confirms the formation of Ge nanoparticles in the annealed films. Development of Ge nanoparticles is also established by photoluminescence (PL) analysis. Surface morphology study is carried out by atomic force microscopy (AFM). It shows the evolution of granular structure of the films with increasing annealing temperature.

Sign in / Sign up

Export Citation Format

Share Document