Phase separation in thin films of end‐grafted block copolymers

Abstract

An atomic force microscopy investigation was carried out on various thick (30–120 nm) polymethyl methacrylate‐b‐polystyrene and poly(2‐(dimethyl amino)ethyl methacrylate)‐b‐polystyrene films prepared via a grafting‐from method. The structure of the films was examined with both topographic and phase imaging. Several different morphologies were observed including a perforated lamellar phase with irregular perforations. In addition, complementary small‐angle X‐ray scattering and reflectometry results measurements on a non‐grafted polymer are presented. Copyright © 2009 John Wiley & Sons, Ltd.

Lateral Phase Separation in Grafted Diblock Copolymer Films

“…These images showed a transition from a disordered phase ( d PS 13 PMMA 100 OH), to increasingly long and thin stripes of PMMA in a matrix of PS as the fraction of PS increases. (Note for all the AFM phase images PMMA appears as the brighter phase. − ) The phase diagram reported for diblock copolymers in the bulk predicts that d PS 13 PMMA 100 OH will be disordered, both d PS 33 PMMA 122 OH and d PS 47 PMMA 135 OH will form a cylindrical phase, and d PS 62 PMMA 69 OH will form a lamellar phase . This is consistent with the AFM results reported here.…”

“…For high grafting densities it is predicted that the minimum molecular weight (or more specifically χ N ) at which nonuniform phases are allowed increases . Such a state was not observed in these films, however it was previously observed in PMMA- b -PS films prepared via a grafting-to method, which had a grafting density of 0.34 nm −2 …”

Synthesis of naringin‐based polymer brushes via seATRP

“…These polymerization methods include ring‐opening polymerization, click reaction, cationic polymerization, anionic polymerization, radical (co)polymerization, reversible addition‐fragmentation chain transfer polymerization (RAFT), nitroxide‐mediated polymerization (NMP), and atom transfer radical polymerization (ATRP), as well as combinations of different methods . Considering these techniques, macromolecular brushes can be synthesized via three main approaches: “grafting through”, “grafting onto”, or “grafting from” . Undoubtedly, “grafting from” is one of the most useful technique which involves attachment of initiator molecules to the backbone and growing of polymer chains via polymerization; therefore, macromolecular brushes with high grafting density can be prepared by using these tactics …”

“…13,[16][17][18][19][20][21][22][23][24][25][26][27][28]30,32,44 Considering these techniques, macromolecular brushes can be synthesized via three main approaches: "grafting through", 2,11,[53][54][55][56] "grafting onto", 54,[57][58][59][60][61][62] or "grafting from". 51,52,[62][63][64][65][66][67][68] Undoubtedly, "grafting from" is one of the most useful technique which involves attachment of initiator molecules to the backbone and growing of polymer chains via polymerization; therefore, macromolecular brushes with high grafting density can be prepared by using these tactics. 13 Citrus-derived flavonoid molecule such as naringin (NG) with eight terminal hydroxyl groups can be used as an efficacious solution to receive functionalized polymers.…”

Structure Variation and Evolution in Microphase-Separated Grafted Diblock Copolymer Films

“…Grafted polymer films (otherwise known as polymer brushes) have garnered much attention due to their desirable physical properties relative to conventional nongrafted films (including improved mechanical robustness and prevention of dewetting), giving grafted films great potential as surface coatings. − Alongside this, advances in polymerization techniques, such as polymerization from surface bound initiators, , and functionalization chemistry, including various “click” reactions, , have allowed for great diversity in the types of films that can be produced.…”