Superhydrophobic surfaces are imperative
in flexible polymer foams
for diverse applications; however, traditional surface coatings on
soft skeletons are often fragile and can hardly endure severe deformation,
making them unstable and highly susceptible to cyclic loadings. Therefore,
it remains a great challenge to balance their mutual exclusiveness
of mechanical robustness and surface water repellency on flexible
substrates. Herein, we describe how robust superhydrophobic surfaces
on soft poly(dimethylsiloxane) (PDMS) foams can be achieved using
an extremely simple, ultrafast, and environmentally friendly flame
scanning strategy. The ultrafast flame treatment (1–3 s) of
PDMS foams produces microwavy and nanosilica rough structures bonded
on the soft skeletons, forming robust superhydrophobic surfaces (i.e.,
water contact angles (WCAs) > 155° and water sliding angles
(WSAs)
< 5°). The rough surface can be effectively tailored by simply
altering the flame scanning speed (2.5–15.0 cm/s) to adjust
the thermal pyrolysis of the PDMS molecules. The optimized surfaces
display reliable mechanical robustness and excellent water repellency
even after 100 cycles of compression of 60% strain, stretching of
100% strain, and bending of 90° and hostile environmental conditions
(including acid/salt/alkali conditions, high/low temperatures, UV
aging, and harsh cyclic abrasion). Moreover, such flame-induced superhydrophobic
surfaces are easily peeled off from ice and can be healable even after
severe abrasion cycles. Clearly, the flame scanning strategy provides
a facile and versatile approach for fabricating mechanically robust
and surface superhydrophobic PDMS foam materials for applications
in complex conditions.
The pyridyltriazole ligand was prepared and applied as a new ligand system for the coordination toward gold(III) cations. The resulting complex showed excellent stability and effective catalytic reactivity for Meyer-Schuster rearrangement of propargyl alcohols and sequential allene halogenation, giving α-haloenones with excellent yields and good E/Z selectivity. More importantly, by using this new gold(III) catalytic system, the challenging α-chloroenone substrates were synthesized in good yields for the first time. This work also permits the avoidance of preparing of acetate derivatives as required in the case of Au(I) catalysts and validates triazole gold(III) complex is an effective new catalyst for alkyne activation.
Polypropylene
(PP) mesh has been used successfully for a long time
in clinical practice as an impressive prosthesis for ventral hernia
repair. To utilize a physical barrier for separating mesh from viscera
is a general approach for preventing adhesions in clinical practice.
However, a serious abdominal adhesion between the mesh and viscera
can possibly occur post-hernia, especially with the small intestine;
this can lead to a series of complications, such as chronic pain,
intestinal obstruction, and fistula. Thus, determining how to prevent
abdominal adhesions between the mesh and viscera is still an urgent
clinical problem. In this study, a dopamine-functionalized polysaccharide
derivative (oxidized-carboxymethylcellulose-g-dopamine,
OCMC-DA) was synthesized; this was blended with carboxymethylchitosan
(CMCS) to form a hydrogel (OCMC-DA/CMCS) in situ at the appropriate
time. The physical and chemical properties of the hydrogel were characterized
successfully, and its excellent biocompatibility was presented by
the in vitro cell test. The combination of this hydrogel and PP mesh
was used in laparoscopic surgery for repairing the abdominal wall
defect, where the hydrogel could become fixed in situ on the PP mesh
to form an anti-adhesion gel-mesh. The results showed that the gel-mesh
could prevent abdominal adhesions effectively in the piglet model.
Moreover, the histology and immunohistochemical staining proved that
the gel-mesh could effectively alleviate the inflammation reaction
and deposition of collagen around the mesh, and it did not disturb
the integration between mesh and abdominal wall. Thus, the gel-mesh
has superior tissue compatibility.
On-board the Landsat-8 satellite, the Thermal Infrared Sensor (TIRS), which has two adjacent thermal channels centered roughly at 10.9 and 12.0 μm, has a great benefit for the land surface temperature (LST) retrieval. The single-channel algorithm (SC) and split-window algorithm (SW) have been applied to retrieve the LST from TIRS data, which need the land surface emissivity (LSE) as prior knowledge. Due to the big challenge of determining the LSE, this study develops a temperature and emissivity separation algorithm which can simultaneously retrieve the LST and LSE. Based on the laboratory emissivity spectrum data, the minimum-maximum emissivity difference module (MMD module) for TIRS data is developed. Then, an emissivity log difference method (ELD method) is developed to maintain the emissivity spectrum shape in the iterative process, which is based on the modified Wien's approximation. Simulation results show that the root-meansquare-errors (RMSEs) are below 0.7 K for the LST and below 0.015 for the LSE. Based on the SURFRAD ground measurements, further evaluation demonstrates that the average absolute error of the LST is about 1.7 K, which indicated that the algorithm is capable of retrieving the LST and LSE simultaneously from TIRS data with fairly good results.
OPEN ACCESSRemote Sens. 2015, 7 9905 Keywords: Landsat-8; TIRS; land surface temperature (LST); land surface emissivity (LSE); minimum-maximum emissivity difference method (MMD method); emissivity log difference method (ELD method); MODTRAN; SURFRAD
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