Tuning the aggregation behavior of pH-responsive micelles by copolymerization

Abstract

Amphiphilic diblock copolymers, poly(2-(diethylamino)ethyl methacrylate-co-2-(dimethylamino)ethyl methacrylate)-b-poly(2-(dimethylamino)ethyl methacrylate), P(DEAEMA-co-DMAEMA)-b-PDMAEMA with various amounts of DEAEMA have been synthesized by RAFT polymerization. Their micellization in water has been investigated by scattering measurements over a wide pH range. It appeared that the polymers self-assembled into pH sensitive star like micelles. For a given composition, when the pH is varied the extent of aggregation can be tuned reversibly by orders of magnitude. By varying the copolymer composition in the hydrophobic block, the onset and extent of aggregation were shifted with respect to pH. This class of diblock copolymer offers the possibility to select the range of stimuli-responsiveness that is useful for a given application, which can rarely be achieved with conventional diblock copolymers consisting of homopolymeric blocks.

Amphiphilic block copolymer self‐assemblies of poly(NVP)‐b‐poly(MDO‐co‐vinyl esters): Tunable dimensions and functionalities

“…Calibration was achieved with filtered toluene and the background was measured with filtered solvent (NaCl 0.1 M). The hydrodynamic radius, R h , and aggregation number, N agg of the self‐assemblies were calculated using the algorithm method as previously reported . TEM samples were prepared on graphene oxide (GO)‐coated carbon grids, which allows high contrast TEM images to be acquired without staining.…”

Micellar nanoparticles with tuneable morphologies through interactions between nucleobase-containing synthetic polymers in aqueous solution

“…Also, the core sizes R core of the micelles also showed the same trend (Table S2 †). We propose that the increasing hydrophilic volume ratios (upon formation of the A : T complementary interactions) lead to smaller N agg values, 66 which also contributes to the reorganization to smaller micelles due to the increase of polymer curvature. Meanwhile, the average aggregation number of the micelles was significantly different from the expected value for a mixture of non-interacting micelles which could be calculated according to eqn (4), where c is the weight concentration of the copolymers in solution.…”

Highlighting the Role of the Random Associating Block in the Self-Assembly of Amphiphilic Block–Random Copolymers

“…31 Their diblock architecture leads to the formation of well-defined aggregates, whereas the randomness of the associating block allows finetuning of the self-assembling properties. 32−36 The block− random architecture has been used by Bendejacq, 37 Wright, 38 Gotzamanis, 39 and ourselves 40,41 to control the structure or dynamics of self-assembly of amphiphilic block copolymers. In our research group we have studied diblock and triblock copolymers consisting of a pure hydrophilic poly(acrylic acid) (PAA) block connected, respectively, to one or two associating random blocks of n-butyl acrylate (nBA) and acrylic acid (AA): P(nBA (1−x) -stat-AA x ) 100 -b-PAA 100 (DHx) and P(nBA ( 40,41 Pure PnBA-b-PAA diblocks formed frozen aggregates 42,43 unable to exchange unimers due to the strong hydrophobic character of the pure PnBA block, but DHx and THx formed aggregates with exchange rates that could be controlled by the pH.…”