Adhesion and Friction Mechanisms of Polymer Surfaces and Thin Films

Recent advances in fabricating injectable hydrogels via tunable molecular interactions for bio-applications

“…Force-measuring techniques, such as surface forces apparatus (SFA) [75][76][77][78] and atomic force microscopy (AFM), [79][80][81][82] allow for the direct measurement of intermolecular interactions, which enables a quantitative understanding of the self-healing behaviors of injectable hydrogels. Specifically, SFA allows in situ and realtime force measurements between opposing surfaces in a vapor or a fluid with an absolute surface separation precision of less than 0.1 nm with a force sensitivity of o10 À8 N. [83][84][85][86][87][88][89] On the other hand, AFM allows force measurements between a nanoscopic or microscopic probe and a substrate surface with a typical force sensitivity of 10 À11 N. [90][91][92][93][94] The AFM probe can also be functionalized to perform direct force measurements at the single-molecule level, allowing quantification of molecular interactions among different components in the hydrogel at the molecular level. [95][96][97] Conventional preformed hydrogels are prone to deformation and damage under high shear pressure during the injection process due to their limited mechanical properties, which will damage their structural integrity and eventually lead to the loss of hydrogel functionality.…”

Formation of Balloon with Porous Structures in NaCl Vapor Assisted by Amphiphilic Polymer for Stent Delivery System

“…Regarding the stent‐gripping mechanism, force is applied in the direction normal to the stent radius when mounted, while the delivery system is in face‐to‐face contact. [ 13 ] Here, the adhesion layer is deformed similarly to the contact shape, and the contact area is increased so that the friction coefficient increases simultaneously. To realize this selective deformation mechanism, it is essential to create a porous structure that can be easily deformed by an external force when applied to the adhesive layer.…”

Study of conducting ITO thin film deposition on flexible polyimide substrate using spray pyrolysis

“…No significant change in the surface morphology of the deposited film was observed after the peel off test which suggests that the bonding was fairly strong. These results can be explained on the basis of the van der Waal's interaction between the metal oxide film and the PI substrate [41]. …”