The control of surface wettability through a combination of surface roughness, chemical composition, and structural modification has attracted significant attention for antifogging and antibacterial applications. Herein, a two-step spin-coating method for amphiphilic organic−inorganic hybrid materials with incorporated transition metal ions is presented. The coating solution was prepared via photochemical thiol−ene click reaction between the mercapto functional group in trimethylolpropane tris(3-mercaptopropionate) and the vinyl functionalized silica precursor 3-(trimethoxysilyl)propyl methacrylate. In the first step of coating, a glass substrate was coated using a solution of metal nitrate hydrates and subsequently showed hydrophobic properties. As the second step, the spin-coated glass substrate was further coated with silica nanoparticles (SiO 2 NPs) and polycaprolactone triol (PCT) suspension, where the contents of SiO 2 NPs were fixed at 0.1 wt %, unless otherwise noted. The coated substrate exhibited hydrophilic properties. For comparison, the coating was also formulated with the SiO 2 NPs/PCT suspension without SiO 2 NPs and with 0.5 wt % SiO 2 NPs as well as by adjusting different coating layer thicknesses. The surface morphology and chemical compositions of the obtained coating materials were analyzed by field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The transparency and static contact angle of coated samples were measured by UV−visible spectrophotometry and drop shape analysis, respectively. It was concluded that our novel hybrid coating materials exhibited excellent antibacterial and antifogging properties with extremely high scratch resistance and transparency.
The adsorption behavior
of an organic dye, metanil yellow (My),
from water using micro–nano silica particles (MNSPs) was investigated.
MCM-41-like (Mobil Composition of Matter No. 41) MNSPs were synthesized
using tetraethoxy orthosilicate as a silica source and hexadecyltrimethylammonium
bromide (CTAB) as a surfactant under basic conditions. Comparative
studies were performed to assess the adsorption behaviors of the organic
dye using the as-synthesized MCM-41 before the removal of CTAB and
MCM-41, either after one, two, and three times of chemical etching
or after calcination. My was adsorbed more effectively from water
on the as-synthesized MCM-41 without the removal of the surfactant
than on MCM-41 after the removal of the surfactant by chemical etching
or calcination. In addition, MCM-41 after removing the surfactant
by one-time chemical etching in the presence of hydrochloric acid
also showed better adsorption of My from water than MCM-41 after removing
the surfactant by further two and three times of chemical etching
or calcination. For comparison, other kinds of dye molecules with
different chemical structures such as methylene blue (Mb) and rhodamine
B (Rb) were also used to check the possibility of adsorption of various
dyes by the CTAB-supported MNSPs. To better understand the reason
behind the adsorption phenomena, detailed studies on the kinetics
and thermodynamics of adsorption of the MNSPs were performed. Excellent
adsorption of My was observed at concentrations up to 100 mg L
–1
at 25 °C, whereas the adsorption was lower at
higher concentrations of the My dye. Furthermore, enhanced My dye
adsorption was observed at higher concentrations by increasing the
adsorption temperature. It can be concluded that the MNSPs exhibited
efficient adsorption of My, when the MNSPs are used without the removal
of the surfactant and any further modifications, suggesting that the
surfactant played key roles in the effective adsorption of the anionic
dye. The as-synthesized MCM-41 was, however, not a good adsorbent
for cationic dyes such as Mb and Rb.
Nanotechnology is being regarded as an emerging technology for smart and active food packaging systems, which can apply for advanced gas/moisture barrier, anti-bacterial platforms. Nano-enabled approaches including nanomaterials and nanofabrications have been used mainly to control the shape and surfaces of platforms in nanoscale for enhancing the function of the food packaging systems. In this review, we summarized current nanotechnologies for smart and active food packaging systems with focus on their applications. Finally, new perspectives of nanotechnology-based smart and active food packaging systems are discussed.
Poly(3-hydroxybutyrate) (PHB) is a biodegradable and biocompatible bioplastic. Effective PHB degradation in nutrient-poor environments is required for industrial and practical applications of PHB. To screen for PHB-degrading strains, PHB double-layer plates were prepared and three new
Bacillus infantis
species with PHB-degrading ability were isolated from the soil. In addition,
phaZ
and
bdhA
of all isolated
B. infantis
were confirmed using a
Bacillus
sp. universal primer set and established polymerase chain reaction conditions. To evaluate the effective PHB degradation ability under nutrient-deficient conditions, PHB film degradation was performed in mineral medium, resulting in a PHB degradation rate of 98.71% for
B. infantis
PD3, which was confirmed in 5 d. Physical changes in the degraded PHB films were analyzed. The decrease in molecular weight due to biodegradation was confirmed using gel permeation chromatography and surface erosion of the PHB film was observed using scanning electron microscopy. To the best of our knowledge, this is the first study on
B. infantis
showing its excellent PHB degradation ability and is expected to contribute to PHB commercialization and industrial composting.
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