Polydimethylsiloxane (PDMS) has many advantages, but the friction coefficient generated by contact with the counter material is high. The purpose of this study is to reduce the friction coefficient by forming hierarchical micro/nanopatterns on the PDMS surface using the imprinting method. In addition, the optimum conditions for reducing the friction coefficient by controlling the sliding speed and normal load were determined. After contacting flat bare PDMS and hierarchical micro/nanostructured PDMS with a counter tip made of polyurethane (PU), the change in friction with sliding speed and vertical load was evaluated. Under normal load conditions, the average friction coefficient of the bare PDMS decreased as the sliding speed increased, and that of the patterned PDMS slightly increased. Regardless of the sliding speed, the friction coefficient decreased as the normal load increased for both specimens. At a sliding speed of 4 mm/s under a load of 10 mN, the friction reduction effect of the pattern structure was the largest at 79%. Overall, the greatest friction reduction effect (84%) was confirmed in patterned PDMS with the lowest friction coefficient under the conditions of 4 mm/s, 50 mN, compared to bare PDMS with the highest friction coefficient under the conditions of 4 mm/s, 10 mN.
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http://dx.doi.org/10.3390/ma15248736 | DOI Listing |
Ann Biomed Eng
January 2025
School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
Purpose: To evaluate the mechanical wear of cartilage with different types of degradation.
Methods: Bovine osteochondral explants were treated with interleukin-1β (IL-1β) to mimic inflammatory conditions, with chondroitinase ABC (ChABC) to specifically remove glycosaminoglycans (GAGs), or with collagenase to degrade the collagen network during 5 days of culture. Viscoelastic properties of cartilage were characterized via indentation.
Sci Rep
January 2025
Department of CSE, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India.
The composition of the metal-polymer friction pair is carefully considered for interacting with water and hydrogen, ensuring the metals electrode process potential remains below waters in a neutral medium. Simultaneously, adherence to defined chemical composition ratios for the metal-polymer materials is crucial. This analysis is conducted under conditions of thermal stabilization, characterized by a minimal temperature gradient across the rim thickness within an equivalent thermal field.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu, Sichuan 610065, P.R. China.
Silicone rubber (SR) holds significant potential for everyday wearable devices due to its inherent sweat resistance and flexibility. However, its broader applicability is constrained by poor oil resistance and a suboptimal slip performance. In this study, we developed an SR with durable oil resistance and enhanced slip properties by forming a covalently bonded barrier layer on its surface through a one-step in situ fluorination reaction using F/N.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Faculty of Marine Engineering, Gdynia Maritime University, 81-225 Gdynia, Poland.
Composites are increasingly being modified with various types of fillers and nanofillers. These materials have attracted much attention due to the improvement in their properties compared to traditional composite materials. In the case of advanced technologies, adding additives to the matrix has created a number of possibilities for use in many industries, from electronics to mechanics.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Department of Civil Engineering, University of Texas Rio Grande Valley, Edinburg, TX 78539, USA.
This paper focuses on the theoretical and analytical modeling of a novel seismic isolator termed the Passive Friction Mechanical Metamaterial Seismic Isolator (PFSMBI) system, which is designed for seismic hazard mitigation in multi-story buildings. The PFSMBI system consists of a lattice structure composed of a series of identical small cells interconnected by layers made of viscoelastic materials. The main function of the lattice is to shift the fundamental natural frequency of the building away from the dominant frequency of earthquake excitations by creating low-frequency bandgaps (FBGs) below 20 Hz.
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