This paper examines the time and frequency response characteristics of two-arm micromachined thermal actuators. Two types actuators are considered: hot/cold arm 'V' or 'chevron' shaped A heat transfer equation governing temperature profile along is derived. Equations for constants responses presented. The measured experimentally compared to analytical predictions.

In the past two years, there have been a large number of publications on topic biomimetic dry adhesives from modeling, fabrication and testing perspectives. We review compare most recent advances in these materials. While is increased convergence consensus as to what makes good adhesive, materials still challenging, particularly for anisotropic or hierarchal designs. Although qualitative comparisons between different adhesive designs can be made, quantifying exact performance rating each...

This article describes a new principle for designing soft or 'semisoft' pneumatic actuators: SLiT (for SLit-in-Tube) actuators. Inflating an elastomeric balloon, when enclosed by external shell (a material with higher Young's modulus) containing slits of different directions and lengths, produces variety motions, including bending, twisting, contraction, elongation. The requisite pressure actuation depends on the length slits, this dependence allows sequential controlling applied pressure....

We present a low-cost, large-scale method of fabricating biomimetic dry adhesives. This process is useful because it uses all photosensitive polymers with minimum fabrication costs or complexity to produce molds for silicone-based A thick-film lift-off used define using AZ 9260 photoresist, slow acting, deep UV sensitive material, PMGI, as both an adhesion promoter the photoresist and undercutting material mushroom-shaped fibers. The benefits this are ease fabrication, wide range potential...

Gecko-inspired surfaces are smart dry adhesive that have attracted much attention because of their wide range potential applications. However, strong frictional force, rather than is frequently targeted in most research this area. In study, the interfacial and properties a gecko-inspired mushroom-shaped polyurethane pillar array surface been systematically characterized to design control adhesion by considering nanoscale adhesion, microscale structural compliance deformation, macro-scale...

SUMMARY This paper presents a novel robotic platform, Abigaille II, designed to climb vertical surfaces using dry adhesion. II is lightweight hexapod prototype actuated by 18 miniaturized motors. The robot's feet consist of adhesive patches, which have microhairs with mushroom-shaped caps fixed on the top millimeter-scale flexible posts. A pentapedal gait used flat as this maximizes number legs in contact surface. can however also walk other gaits, including tripod gait.

Purpose This paper aims to target print functionally gradient materials (FGM) devices made of immiscible polymers in multi-material fused deposition modelling (FDM) systems. The design is intended improve adhesion dissimilar thermoplastics without the need for chemical compatibilization so that filaments from many different sources can be used effectively. Therefore, there a invent an alternative solution printing multiple FDM system with desired adhesion. Design/methodology/approach In this...

Dry adhesives have attracted much attention because of their repeatable and reversible attachment. Many research groups made fruitful achievements in fabricating designing various dry adhesives. However, most these studies focus on imitating bioinspired geometry to achieve this smart adhesion, neglecting the contact interface control through peeling motion. Here, we present an alternative design switchable adhesion basis controlling areas. This unique includes micropillars array with large...

Liquid‐metal alloys are now extensively used for stretchable electronic applications due to their superior electrical conductivity, non‐toxicity, and mechanical stability in micro‐channels. Needle‐injection direct‐writing the most popular techniques patterning micro‐structured liquid metal alloys. However, embedded channels often require a very high pressure inject liquid‐metal, direct writing by dispensing is relatively complex low viscosities surface tension of which cause normally...

This study focused on developing pigmented linear low-density polyethylene (LLDPE) sheets while preserving their mechanical properties and infrared (IR) transparency. Six pigments-ZnO, ZnS, TiO2, FeO yellow, light brown, dark brown-were each mixed with (PE) wax in a 1:1 ratio blended LLDPE at concentrations of 1, 3, 5 wt%. Tensile strength tests showed minimal changes lower pigment concentrations, values near that pure (14 MPa), slight reductions IR transparency tests, conducted using both...

We demonstrate for the first time a wafer scale, directly molded anisotropic dry adhesive made of silicone that can be produced in two-mask process. peel strength this is dependent on amount overhang thin flexible cap top each fiber. By precisely placing center offset to supporting post, altered when pulled off different directions.

We present a novel fabrication method for the production of biomimetic dry adhesives that allows enormous variation in fiber shapes and sizes. The technology is based on deep-UV patterning commercial acrylic with semi-collimated light available from germicidal lamps, combined careful processing conditions, material selection developer choices to produce relatively high-aspect-ratio fibers overhanging caps large areas. These are used as master mold subsequent silicone rubber negative casting....

Strong, reversible underwater adhesion using gecko-inspired surfaces is achievable through the use of a hydrophobic structural material and does not require surface modification or suction cup effects for this to be effective. Increased energy can aid in dry an air environment but strongly degrades wet via reduction interfacial underwater. A direct comparison structurally identical chemically different mushroom shaped fibers shows that strong, adhesion, even fully wetted, stable state,...

We report in this work a novel reversible bonding technique for elastomeric microfluidic devices by integrating gecko-inspired dry adhesives with channels which greatly enhances the strength of reversibly sealed channels. The concept is applicable to nearly any elastomer and can be used bond against smooth surface allows van der Waals interactions. It does not require solvents or glues sources plasma activation thermal-compressive loading aid process achievable at zero extra cost. also...

Abstract This paper describes the fabrication of elastomeric three‐dimensional (3D) structures starting from two‐dimensional (2D) sheets using a combination direct‐ink printing and relaxation strain. These are fabricated in two‐step process: first, inks deposited as 2D on stretched sheet, second, after curing inks, strain sheet causes it to deform into 3D shape. To predict bending objects with this technique, simple mechanical model is developed. The strategy initially materials fabricate...

The sustainable growth of industries that consume a large amount fresh water relies on developing energy-efficient wastewater treatment processes. Nanofiltration (NF) has been widely considered for such purposes; however, the fabrication highly permeable NF membranes while maintaining high removal rate ions and organic matter remains big challenge. Here, we fabricated micropatterned thin-film composite (TFC) using two-step process. First, hydrogel-facilitated phase separation (HFPS) method...

In many cases, such as in the instance of climbing robots or temporary adhesives, there is need to be able dynamically control level adhesion a biomimetic dry adhesive can provide. this study, effect changing backing layer stiffness examined. Embedding phase change material within synthetic sheet allows tailored at different points preload and cycle. Larger contact areas more equal load sharing between fibres achieved by increasing after initial deformation when loaded its softened state....

Abstract The effectiveness of biomimetic dry adhesives at different ambient pressures was investigated. Biomimetic have great potential for space applications but there been few studies on how these perform in low-pressure environments. best performing geometry with respect to normal adhesion has previously determined be mushroom shaped fibers, the pressure sensitivity designs unclear – some groups reporting dependent adhesion, and others claiming no effect. We compared microscale polymer...