The aim of this work was to investigate the effect of glycerol concentration on mechanical
and physical properties of gellan gum (GG) biofilm. The biofilm was prepared using solvent
casting method and the effective glycerol concentration was found to be within 30-50%
w/w (based on GG weight). At 60 and 70 w/w% of glycerol, the films started to distort
because the films was flexible and brittle. As glycerol concentration was increased the tensile
strength (TS) and Youngs modulus (E) of films decreased. Somehow, elongation at break
(EAB), water vapor transmission rate (WVTR) and swelling of films was increased. Glycerol
plasticized GG biofilm was thermally stable and flexible, proposed its can be exploited as
film-forming material and with optimized glycerol concentration it has good mechanical and
physical properties for edible biofilm.
This study examined the effect of honey in gellan gum (GG) hydrogel containing virgin
coconut oil (VCO). Their mechanical, physical, thermal properties and in-vivo healing potential
on dermal wounds were investigated. The compression performance results show that
the inclusion of honey into gellan gum incorporated VCO (GGVCOH) hydrogel improved
the compressive stress of the materials by 3-fold and workable to be applied on the different
contours of human body. Swelling ratio of GVCO hydrogels increased upon addition of
honey, and water transmission rates (WVTRs) values of all hydrogels were in the range of
112-132 g m−2 d
−1
, in which comparable to WVTRs values of commercial wound dressings.
Thermal behavior shows the inclusion of honey in GVCO hydrogels improved the thermal
stability particularly at high concentration. In-vivo healing on dermal wounds exhibits that
the inclusion of honey accelerated the wound closure and shows complete neo-epidermal
of the wounds. The GVCOH hydrogel has shown promising results to treats acute wound
treatments.
The new microelectronic products require the silicon (Si) wafer to be thinned to less than
150 µm in thickness. Residual defect on the wafer surface that leads to wafer breakage with
a rough surface still be produced by mechanical grinding. Thus, chemical etching method is
essentially applied to produce a reliable thin wafer with smooth surface of desired thickness.
In this work, we studied the wet chemical etching effect of different HNO3 concentrations on
total thickness and weight loss, etch rate, morphological and structural properties of Si wafer
in the mixtures of HNO3 and HF. The results showed that the total thickness and weight
loss increases with the increasing of HNO3 concentration and etching time. Higher HNO3
concentration causes higher etch rate, and the etch rate decreases at prolonged etching time.
A smoother and clearer homogeneous Si surface image was observed by optical microscope as
the etching time and HNO3 concentration increase. XRD analysis shows that the intensity
of etched Si wafer is higher than the pure one, which might indicate the smoother surface
formation after etching. The findings of present study can be valuably referred to produce
a reliable and desired Si thin wafer which is crucial in integrated circuit fabrication.