Surface Modification Inspired by Malayopython Reticulatus for Friction Control

This research is to study the frictional characteristics of a real Malayopython Reticulatus snake ventral scales and to evaluate its feasibility as an inspiration for surface modification designs. Two types of experiments were carried out at different sliding directions and surfaces to analyze the frictional characteristics of snake ventral scales. From this study, snakeskin demonstrates frictional anisotropy and it is prominent under wet condition. Based on these findings, surface designs inspired by snakeskin is suitable for parts or components that are subjected to directional friction especially in wet conditions

Evaluation of Antibacterial Activities for Poly-Dl-Lactic Acid Nanosheet on the Biomimetic Sharkskin

The purpose of this study is to quantitatively examine whether antimicrobial activity varies with the thickness of the PDLLA nanosheets when placed on a PDMS surface with or without biomimetic shark skin surfaces. Sharks are known to have an antifouling property due to the rivulet structure of grooves spaced tens of μm apart covering their skin. The riblet structure reduces the area to which organisms adhere and prevents contact with small dirt and bacteria. In this study, a PDMS elastomer-embedded stamping method consisting of polydimethy lsiloxane PDMS was used to achieve the biomimicry of sharkskin. The surface morphology before and after the nanosheet was applied was then observed with a scanning electron microscope to create a bacterial mass reference line to evaluate its antimicrobial activity. As a result, a decrease in antimicrobial activity was observed in the biological model compared to the flat surface. In addition, a small decreasing trend in antimicrobial effect was seen when the film thickness exceeded 100 nm in nanosheets with different film thicknesses, indicating that the antimicrobial activity on the surface increased as the film thickness became thicker and less able to follow the surface irregularities

Friction measurement of modified PDMS surfaces inspired by Malayopython Reticulatus

The lack of limbs on snakes enables its ventral scales to be in almost constant contact with the substrate. Their skin is presumably adapted to generate high and low friction to slither. This frictional characteristics in snakes were hypothesized to be contributed by the be tooth-shaped or denticle-like microstructures found on the snake ventral scales. The frictional properties of the microstructures found on snake ventral scales was studied and its feasibility as an inspiration for surface modifications was observed. This study was carried out to analyze the frictional anisotropy exhibit by the snake ventral scale microstructures and also how it changes the frictional properties of the PDMS surface when the microstructures are replicated on to it. The PDMS embedded-elastomeric stamping method was used in this experiment to replicate the snake ventral scales onto the PDMS. Based on the data collected the microstructures on the snake ventral scales does exhibit frictional anisotropy. The PDMS with replicated snakeskin microstructures displays higher COF compared to PDMS with smooth surface. When sliding on most types of surfaces, the COF of real snakeskin and replicated snakeskin is higher if the surface is semi wet. Whereas for smooth PDMS the COF is lower when the surfaces are semi wet. Generally, from both experiments, when the replicated snakeskin is sliding on the surface in the lateral direction, it is observed that the COF is the lowest followed by the caudal then the rostral direction

Antibacterial Properties of Snakeskin Inspired PDMS Surfaces Layered with Poly-DL-Lactic Acid Nanosheet

The increment of sterilization resistant bacteria minimizes the effectiveness of disinfectants which leads researchers into studying other means in minimizing bacterial contamination on surfaces. Hence, this study plans to investigate surfaces with the ability to discourage bacterial adhesion and reduces the need for frequent sterilization. This study tested the feasibility of applying snakeskin inspired microstructures onto a polydimethylsiloxane (PDMS) surface to reduce bacterial adhesion and increase its antibacterial properties. In theory, the microstructure of snakeskin is smaller or about the same size as a bacterium making it unfeasible for bacterial adhesion. The embeddedelastomeric stamping method was used for the biomimicry of snakeskin onto PDMS surfaces. The replicated snakeskin and controlled (no microstructure) PDMS samples were layered with Poly-DL-lactic acid (PDLLA) nanosheet of different thickness. Then, the morphology of the surfaces was observed using a scanning electron microscope. The surface of the samples was tested with Staphylococcus aureus and Bacillus with compliance of the ISO 22196 standard to evaluate the antimicrobial activity. Our results revealed, surfaces with snakeskin microstructures displayed a 16% reduction in bacterial adhesion compared to flat PDMS. Whereas the presence of nanosheet does not significantly affect the adhesion of bacteria on the replicated snakeskin. These findings suggest that surfaces with the presence of snakeskin microstructures possess antibacterial property