Micelle formation of randomly grafted copolymers in slightly selective solvents

Abstract

Articles you may be interested inDepletion-induced surface alignment of asymmetric diblock copolymer in selective solvents Amphiphilic surfactants, molecules with chemical moieties that interact differently with the solvating medium, are important for technological applications and ubiquitous in biology. Understanding how to control surfactant properties is, therefore, of wide-ranging importance. Using a combination of light scattering experiments and field theory, we demonstrate that the behavior of polymeric surfactants can be controlled sensitively by manipulating molecular architecture. We find that branched polymeric amphiphiles can be much better surfactants than traditional linear analogs. This is indicated by micelle formation in solvents that are very slightly selective for the backbone of the branched molecule. Our experimental and theoretical findings also suggest that, for a given chemistry and architectural class, surfactant properties of polymeric amphiphiles are very sensitive to subtle changes in architectural features. Specifically, we find that choosing a particular branching density optimizes the propensity for micelle formation. The sensitivity of macromolecular surfactant properties to molecular architecture can perhaps be profitably exploited in applications wherein only certain chemical moieties are allowed. The physical origin of this sensitivity is the importance of conformational entropy penalties associated with the pertinent self-assembly process. This is in contrast to self-assembly of small molecule systems where conformational entropy is not of such significance.

HA (Hydrophobic/Amphiphilic) Copolymer Model: Coil−Globule Transition versus Aggregation

“…Meanwhile, it is far from clear that the desired result can be in principle accessible on the basis of simple linear models in the case of electroneutral heteropolymers, since in this case there are no real ways of creating the insurmountable (or very high) energy barriers, preventing large-scale aggregation. It is interesting that this conclusion is in general agreement with the recent study 62 where it was shown (both experimentally and theoretically) that branched polymer amphiphiles are normally much better surfactants than traditional linear analogues.…”

Thermally Induced Gelation of Poly(acrylamide) Grafted with Poly(N-isopropylacrylamide): A Small-Angle Neutron Scattering Study

“…37,40 Reference 37 deals with microphase separation in a semidilute solution of poly-(sodium acrylate) grafted with PEO. The model used in the strong segregation regime indicated that PEO microdomains behave as polydisperse spherical micelles organized in a simple cubic lattice.…”

“…Compared to block associating copolymers that have been studied several times, − the literature is poorer concerning graft copolymers. , Reference 37 deals with microphase separation in a semidilute solution of poly(sodium acrylate) grafted with PEO. The model used in the strong segregation regime indicated that PEO microdomains behave as polydisperse spherical micelles organized in a simple cubic lattice.…”

The phase behavior of comblike block copolymer Am+1Bm/homopolymer A mixtures

“…[1][2][3][4] As a special branched block copolymer, the phase behaviors of comblike block copolymer have been investigated in both experiment and theory. [5][6][7][8][9][10] As we know, the microphase behavior can be controlled by changing the architecture of polymer, [11][12][13] thus changing the structure of comblike block copolymer can also tune the phase behavior. However, It is necessary to accurately synthesize complex molecules in order to obtain the desired behavior, which remains a serious obstacle impeding their commercial exploitation.…”