The Effect of Different Pre-Surface Finishing Method on the Aluminium Anodization of the 6XXX Series Alloy

In this study, the effect of different pre-surface finishing method on the aluminium anodization was investigated for AA 6063 alloy. Within the scope of pre-surface finishing method which is acidic solution concentrations and process time were determined. Acidic solution was determined by using hydrofluoric acid (HF) and nitric acid (HNO3). Also Gresoff LIM-5 LV chemical was used with different concentrations and process time for degreasing process. The etching effect of acidic solution on aluminium samples was investigated. The optimal etching behaviour was obtained with 1.0% concentration of HF and 3.2% concentration of HNO3 at 10 minutes process time. Also optimal surface properties were observed with 1.0% concentration of Gresoff LIM-5 LV at 12 minutes process time. Then anodic oxidation was performed by using 180 g / L sulfuric acid (H2SO4) and 18 volt (V). Surface morphology of the final aluminium profiles were examined with SEM analysis, Roughness, Gloss and Thickness tests.

Self-Photoluminescence of Unzipped Multi-Walled Carbon Nanotubes

Unzipping of carbon nanotubes (CNTs) has been widely explored to obtain new nanocarbon structures with promising properties. In this work, we report that unzipping of CNTs according to the well-established modified Hummers method produces unzipped CNTs (uCNTs) that exhibit self-photoluminescence that depends on the diameter of pristine CNTs. The uCNTs were characterized using FTIR spectroscopy, XRD, XPS, and Raman spectroscopy indicating that unzipping is accompanied by the introduction of defects and oxygen-containing functional groups. The morphology of CNTs and uCNTs was determined by TEM showing longitude unzipping of CNTs. Our study shows that increasing the diameter of pristine CNTs results in decreasing the edge etching effect and decreasing the functionality of uCNTs. Based on the UV-Vis spectra, the band gap of uCNTs was calculated using the Kubelka–Munk function. The band gap of uCNTs increased with decreasing diameter of pristine CNTs. The uCNTs exhibited photoluminescence with a good emission in the visible light region. The uCNTs with the largest band gap and the highest oxygen content had the strongest fluorescence intensity. Moreover, different metal ions produced different degrees of fluorescence quenching for uCNT-15, which verified the self-photoluminescence of uCNTs.

Effects of Synthetic Procedures and Postsynthesis Incubation pH on Size, Shape, and Antibacterial Activity of Copper (I) Oxide Nanoparticles

Copper (I) oxide nanoparticles (Cu2O NP) were synthesized by reducing CuSO4 with glucose in the presence of polyvinyl alcohol as a capping agent. We used three different synthetic procedures with a fast reaction (procedure 1p), a fast-then-slow reaction (procedure 2p), and a slow-then-fast reaction (procedure 3p). The reaction rates were controlled by changing the temperature and the speed of adding reagents. The synthesized Cu2O NP were subsequently incubated for 24 h in a pH 6 solution (Cu2O NP6) or a pH 8 solution (Cu2O NP8) at 5°C. XRD and SEM images analysis revealed that the 1p procedure produced smaller NP, while the 2p procedure produced larger but more uniform NP. The 3p procedure produced the largest NP with a higher size variation. The 24-hour acidic postsynthesis incubation resulted in an etching effect, which reduced the size and size variation of Cu2O NP6. To evaluate the antibacterial activity, E. coli suspensions were mixed with the obtained Cu2O NP (32, 96, or 160 ppm) for different time intervals (1 or 24 h) and then grown on Petri dishes at 37°C for 24 h. Higher doses, smaller sizes of Cu2O NP, and longer contact times with the bacterial suspension resulted in higher inactivation efficiencies. Cu2O NP6 showed higher antibacterial effects at low doses, possibly due to the etching effect and the positive surface charge. Increasing the Cu2O doses from 32 to 96 and 160 ppm noticeably increased the antibacterial effect of the Cu2O NP8, but not significantly for Cu2O NP6. We suggested that the Cu2O NP6 suffered from agglomeration at high doses due to their high surface activity and low surface charges.

Chemical, Thermo-Mechanical and Antimicrobial Properties of DBD Plasma Treated Disinfectant-Impregnated Wipes during Storage

Disinfectant-impregnated wipes are broadly used in hospitals, as an important approach for infection prevention and control. But their ageing performance has rarely been studied. Untreated and Dielectric Barrier Discharge (DBD) plasma pre-treated wiping materials made of nonwoven 100% polyester (W1), nonwoven 55% cellulose/45% polyester (W2) and woven cotton (W3) were impregnated with a quaternary ammonium compound solution (ADBAC) for 30 min, 3, 7, 15, and 30 days of storage time and characterized in term of chemical, thermo-mechanical and antimicrobial efficacy. X-ray photoelectron spectroscopy analysis on the plasma-treated polyester wipes demonstrates the incorporation of reactive oxygen species on the fiber surface. Laser scanning microscopy demonstrates the plasma etching effect in smoothing the surface of the cotton wipe reducing the adsorption of ADBAC. The result showed no significant changes in breaking force and elongation during storage for W1 and W2. However, plasma treatment affects W3 in weft direction reducing the force at break in water and ADBAC treated wipes. Dynamic mechanical analysis results show that ADBAC and plasma treatment have a significant influence in W1 and W3 viscoelastic properties improving the elastic response limiting the polymeric chains mobility and the non-elastic response due to the etching effect, respectively. Overall, the plasma pre-treatment of ADBAC-impregnated wipes is able to enhance the antimicrobial performance and the storage time of polyester-containing wipes.

THE STUDY ON THE O2 PLASMA TREATMENT FOR BONDING OF SU-8 LAYERS

SU-8 is becoming increasingly important for fabrication of lab-on-a-chip devices due to its excellent chemical stability, mechanical, and optical properties. To form a complete SU-8 device, O2 plasma-assisted thermal bonding has been used to bond SU-8 layers. O2 plasma treatment is critical and has a significant influence on the fabrication quality of SU-8 devices. However, to the best of our knowledge, there is no work which analyzed O2 plasma treating process for SU-8 material in depth and systematically. In this study, the influence of O2 plasma treatment on the water contact angle and bonding strength for both un-crosslinked and crosslinked SU-8 layer was investigated in detail. The etching effect of SU-8 layer was also studied. The leakage test demonstrated that there is no gas leakage in the bonded SU-8 layer up to 0.65[Formula: see text]Mpa which indicates the practicability of the proposed SU-8 bonding method.