Effect of hydrophilic chain length on the aqueous solution behavior of block amphiphilic copolymers PMMA‐b‐PDMAEMA

Abstract

A series of amphiphilic block copolymers, polymethyl methacrylate (PMMA)-b-poly [2-(dimethylamino)ethyl methacrylate] (PDMAEMA), were synthesized by atom transfer radical polymerization (ATRP) method. Surface tension, dynamic light scattering (DLS), transmission electron microscope (TEM), and atomic force microscopy (AFM) studies were performed to investigate the aqueous micellar behavior of these block amphiphiles. At a fixed degree of polymerization (DP) of PMMA block (DP ¼ 55), the PDMAEMA block length was found to have a significant influence on the critical micelle concentration (cmc) values and hydrodynamic size of aggre-gates. An increase in the DP of PDMAEMA from 11 to 337, resulted in a decrease in the cmc from 1.44 Â 10 À5 to 5.81 Â 10 À7 M (a factor of almost 24.8), and a decrease in the Z (2R h ) from 85.5 to 15.5 nm (pH ¼ 4), respectively. TEM and AFM results indicated that by changing the soluble block lengths, spherical, short rod, crew-cut, vesicles or large aggregates can be observed in the solution.

Multiple morphologies of a poly(methyl methacrylate)‐block‐poly(N,N‐dimethyl aminoethyl methacrylate) copolymer with pH‐responsiveness and thermoresponsiveness

“…Moreover, they first reported the critical micelle concentration (cmc) dependence on the chemical structure of PMMA‐ b ‐PDMAEMA with non‐protein nitrogen (NPN) fluorescence . Zhang et al . found that the average sizes and micromorphology of PMMA‐ b ‐PDMAEMA aggregates at different pH depended strongly on the solvent nature and the PDMAEMA chain length.…”

Nitroxide‐mediated radical polymerization of methacryloisobutyl POSS and its block copolymers with poly(n‐acryloylmorpholine)

“…This can be justified by the packing parameter theory . Xiao et al . have observed a similar behavior for the micellization of a series of poly(methyl methacrylate)‐ b ‐poly[2‐(dimethylamino)ethyl methacrylate] diblock copolymers with fixed hydrophobic chain length and varying the hydrophilic segment length in aqueous solution, where the micelle size was observed to decrease with increasing the hydrophilic chain length.…”

Synthesis of stimuli-sensitive copolymers by RAFT polymerization: potential candidates as drug delivery systems

“…Of these living polymerization techniques, atom transfer radical polymerization (ATRP) 7 and RAFT 8 are generally considered to be the best strategies to obtain functional polymeric systems for defined applications. Amphiphilic copolymers based on PDMAEMA, such as PMMA-b-DMAEMA 3,9 , PDMAEMA-b-PCL-b-PDMAEMA 10 , PTFEco-PDMAEMA 11 , and PS-b-PDMAEMA 12 , have been described, with the aim of studying self-assembly behavior at different solution pH values. The LCST of PMMA-b-PDMAEMA copolymers synthesized by RAFT was found to be affected by ionic strength, pH and the nature of the ion 3 .…”

“…Zhu et al 12 showed that on adjusting certain parameters, such as the solvent, charge density and pH, specific changes in the structure of the aggregations can be obtained for PS-b-PDMAEMA copolymers obtained by ATRP. Xiao and others synthesized PMMA-b-PDMAEMA by ATRP and investigated the effects of PMMA or PDMAEMA block length on the aggregate formation 9 . However, studies related to new mechanisms of controlled polymerization of VCL are still scarce, due to several factors including the fact that VCL is an unconjugated monomer and its propagating radical is poorly stabilized and, as a consequence, very reactive.…”