Friction enhancement via micro-patterned wet elastomer adhesives on small intestinal surfaces

Abstract

A micro-pillar-based silicone rubber adhesive coated with a thin silicone oil layer is investigated in this paper for developing friction-based clamping mechanisms for robotic endoscopic microcapsules. These adhesives are shown to enhance the frictional force between the capsule and the intestinal wall by a factor of about seven over a non-patterned flat elastomer material. In this study, tests performed on fresh samples of pig small intestine are used to optimize the diameter of the micro-pillars to maximize the frictional forces. In addition, the effects of other factors such as the oil viscosity and applied normal forces are investigated. It is demonstrated that the proposed micro-pillar pattern based elastomer adhesive exhibits a maximal frictional force when the pillar diameter is 140 microm and coated silicon oil has a very high viscosity (10,000 cSt). It is also found that the frictional force of the micro-patterned adhesive increases nonlinearly in proportion to the applied normal force. These adhesives would be used as a robust attachment material for developing robotic capsule endoscopes inside intestines with clamping capability.

Frictional resistance model for tissue-capsule endoscope sliding contact in the gastrointestinal tract

“…Others have extensively studied the effect of capsule diameter, length, speed, normal force, and velocity, all of which were studied to assess model validity in this work. In summary, literature reports that resistance force is directly proportional to capsule speed [21][22][23][24][25][26][27][28][29], diameter [20-24, 29, 30], length [23,29,30], and normal force [21,23,31].…”

Adhesion and anisotropic friction enhancements of angled heterogeneous micro-fiber arrays with spherical and spatula tips

“…Since the discovery of the role of van der Waals forces in biological dry adhesives such as those in insects and geckos in 2002 [2], there has been a surge of interest in developing techniques for fabricating synthetic biomimetic dry adhesive materials for various applications, including climbing robots [8][9][10][11], and medical/surgical applications [12]. Researchers are characterizing biological samples [3,13,14] and are fabricating synthetic adhesive arrays from polymers [15,16], carbon nanotubes [17,18], and organorods [19], using methods such as micro/nano-molding [16,[20][21][22][23][24][25], nano-embossing [26], carbon nanotube growth [17,18], fiber drawing [27], and lithography [15,28].…”

Flat Dry Elastomer Adhesives as Attachment Materials for Climbing Robots

“…The setup includes a motorized micropositioner (Newport, CMA-25CCCL) and a high-resolution load cell (GSO-25; Transducer Techniques, Inc.) [40], [46]. Polyurethane elastomers are viscoelastic, and the proposed elastic models are valid only for very-slow speeds.…”