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Poly(Li‐2‐hydroxyethyl methacrylate)‐ co ‐poly(4‐vinyl pyridine): Molar mass effects on strong electrorheological response
Author(s) -
Yilmaz Hasim,
Unal Halil Ibrahim
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.23588
Subject(s) - electrorheological fluid , molar mass , materials science , polymer chemistry , methacrylate , copolymer , rheology , ionomer , electric field , chemical engineering , composite material , polymer , physics , quantum mechanics , engineering
Electrorheological (ER) fluids display remarkable rheological behavior, being able to convert rapidly and repeatedly from a fluid to a solid‐like when an external electric field (E) is applied or removed. In this study, electrical and ER properties of poly(Li‐2‐hydroxyethyl methacrylate)‐ co ‐poly(4‐vinyl pyridine), poly(Li‐HEMA)‐ co ‐poly(4‐VP), copolymeric salts (ionomers) were investigated. For this purpose six ionomers were synthesized with different molar masses. They were then ground‐milled for a few hours to obtain micron size ionomers. The particle sizes of the ionomers were determined by dynamic light scattering. Suspensions of ionomers were prepared in silicone oil (SO), at a series of concentrations ( c = 5–30%, m/m). The gravitational stability of suspensions against sedimentation was determined at constant temperature ( T = 25°C). Flow times of the suspensions were measured under no electric field ( E = 0 kV/mm), and under an external applied electric field (E ≠ 0 kV/mm) strengths and a strong ER activities were observed for all the poly(Li‐HEMA)‐ co ‐poly(4‐VP)/SO suspensions. Further, the effects of suspension concentration, mole ratios of poly(HEMA) and poly(4‐VP), and the overall molar mass of the copolymers, shear rate, electric field strength, frequency, promoter, and temperature onto ER activities of ionomer suspensions were investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1065–1074, 2006