|제목(영문)||Role of Charges of the Surface-grafted Polymer Chains for Aqueous Lubrication at a Nonpolar Interface|
,Dept. of Mechanical Engineering, Technical University of Denmark
- (Jan Busk Madsen ,Dept. of Mechanical Engineering, Technical University of Denmark ) ▷공저자네트워크등록하기
- (Nikolaos Nikorgeorgos ,Dept. of Mechanical Engineering, Technical University of Denmark ) ▷공저자네트워크등록하기
이승환 (Seunghwan Lee ,Dept. of Mechanical Engineering, Technical University of Denmark ) ▷공저자네트워크등록하기
Charged polymer chains, i.e.，polyelectrolytes，are known to show superior aqueous lubricating properties compared to those of neutral polymer chains，especially in brush conformation. This is primarily because of the incorporation of a large amount of counterions within the polymer layers and the consequently increased osmotic pressure. However, this effect is active only when the polymer chains remain immobilized even under tribostress, which is not realistic for high-contact pressure tribological applications, especially when they are irreversibly immobilized on tribopair surfaces. In contrast, with free polymers, which can be included as surface-active additives in the base lubricant (water), long-term lubricating performance based on “self-healing” properties is readily expected. In order to assess whether the superior aqueous lubricating properties of polyelectrolyte chains are valid for free polymers too, this study reviews recent studies on the tribological properties of many charged biopolymer and synthetic copolymers at a nonpolar, hydrophobic interface . In contrast to the irreversibly immobilized polyelectrolyte chains，free polyelectrolyte chains show inferior aqueous lubricating properties compared to their neutral counterparts owing to charge accumulation and the consequently impeded surface adsorption on the nonpolar surface. Nevertheless, bovine submaxillary mucin (BSM)，a representative biopolymer, shows a sufficiently effective surface adsorption and aqueous lubricating capabilities even at neutral pH without losing the polyanionic characteristics.
|keyword||polymer brush, charge，aqueous lubrication, polyelectrolyte|