Tribological Properties of Double-Network Gels Substituted by Ionic Liquids

Since human body joints have a gel-like structure with low friction that persists for several decades, hydrogels have attracted much interest for developing low-friction materials. However, such advantages can hardly be realized in industrial usage because water in the gel evaporates easily and the...

Full description

Saved in:
Bibliographic Details
Published in:Lubricants 2018-10, Vol.6 (4), p.89
Main Authors: Arafune, Hiroyuki, Muto, Fumiya, Kamijo, Toshio, Honma, Saika, Morinaga, Takashi, Sato, Takaya
Format: Article
Language:English
Subjects:
Adhesion
Coefficient of friction
Design
double-network gel
electrostatic interaction
Electrostatic shielding
Friction
Gels
Glass
Hydrogels
Industrial applications
ionic liquid
Ionic liquids
Ions
low friction
Lubricants & lubrication
Polymerization
Polymers
Solvents
Stress concentration
Substitutes
Thermodynamic properties
Thermogravimetric analysis
Tribology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Since human body joints have a gel-like structure with low friction that persists for several decades, hydrogels have attracted much interest for developing low-friction materials. However, such advantages can hardly be realized in industrial usage because water in the gel evaporates easily and the gel deswells. The substitution of water with an ionic liquid (IL) is one of the effective ways to overcome this problem. In this study, we substituted water in a double network (DN) hydrogel with 3-ethyl-1-methyl-imidazolium ethylsulfate (EMI-EtSulf), a hydrophilic IL, via a simple solvent exchange method to obtain a DN ion gel. A compressive test and thermogravimetric analysis showed that the DN ion gel has a high compression fracture stress and improved thermal properties, with the difference in 10% loss of temperature being ΔT10 = 234 °C. A friction test conducted using a reciprocating tribometer showed that the friction of a glass ball/DN ion gel was relatively higher than that of a glass ball/DN hydrogel. Because the minimum coefficient of friction (COF) value increased after substitution, the increase in polymer adhesion caused by the electrostatic shielding of the surface moieties of glass and poly 2-acrylamidomethylpropanesulfonic acid (PAMPS) was considered the main contributor to the high friction. As the COF value decreased with increasing temperature, the DN ion gel can achieve low friction via the restriction of polymer adhesion at high temperatures, which is difficult in the DN hydrogel owing to drying.
ISSN:2075-4442
2075-4442
DOI:10.3390/lubricants6040089