Effects of Ionic Strength and Ion Specificity on the Interface Behavior of Poly(dimethylaminoethyl methacrylate)–Poly(lauryl methacrylate)

Abstract

The ion specificity effect on the water solubility of poly(N-isopropylacrylamide)-containing copolymers complies with the Hofmeister series, which is applicable to other copolymers or not need to be explored. In this work, effects of ionic strength under acidic conditions and ion specificity under alkaline conditions on the air/water interface behavior of two amphiphilic diblock copolymers poly-(dimethylaminoethyl methacrylate)−poly(lauryl methacrylate) (PDMAEMA-PLMA) were systematically studied. Under acidic conditions, the surface pressure−area isotherms of a predominantly hydrophilic copolymer are insensitive to ionic strength. In contrast, the isotherms of a predominantly hydrophobic copolymer successively shift to the large, small, and large molecular area with the increase of ionic strength. Under alkaline conditions, the interfacial stretch degrees of PDMAEMA chains of two copolymers change with salt species and concentrations, which do not comply with the Hofmeister series. All of the Langmuir−Blodgett films of the former copolymer exhibit separate circular micelles. Nevertheless, those of the latter copolymer obtained under alkaline conditions exhibit various distinctive morphologies such as separate circular micelles, large separate PLMA cores within large PDMAEMA domains, and large PLMA domains/aggregates surrounded by short PDMAEMA shells. It can be attributed to the high deformability of PLMA chains, the ion specificity effect on the stretch degree of PDMAEMA blocks, and their underwater solubility upon compression.

Controllable-assembled functional monolayers by the Langmuir–Blodgett technique for optoelectronic applications

“…Based on the basic monolayer assembly process, an overview of how to achieve highquality LB films is provided. [51][52][53][54][55][56]…”

Closely Packed Core–Shell Micelle Structures of Double Hydrophilic Miktoarm Star Copolymers at the Air–Water Interface

“…Many researchers have demonstrated the ability of amphiphilic block copolymers to self-assemble into various monolayers at the air–water interface, − and the formation of nanoaggregates can be primarily controlled by modifying the polymer composition. Some common linear copolymers, such as polystyrene- block -poly­(ethylene oxide) (PS- b -PEO), − polystyrene- block -poly­(methyl methacrylate) (PS- b -PMMA), − and polystyrene- block -poly­(2-vinylpyridine) (PS- b -P2VP), , have been comprehensively studied.…”