Amphiphilic Model Conetworks Based on Combinations of Methacrylate, Acrylate, and Styrenic Units:  Synthesis by RAFT Radical Polymerization and Characterization of the Swelling Behavior

Abstract

Reversible addition-fragmentation chain transfer (RAFT) polymerization was employed for the preparation of homopolymer and copolymer (co)networks based on four monomer units, belonging to three monomer types: methacrylates, acrylates, and styrenics. In particular, n-butyl methacrylate and 2-(dimethylamino)ethyl methacrylate (DMAEMA) (hydrophobic and hydrophilic-ionizable methacrylate monomers, respectively), n-butyl acrylate (hydrophobic) and styrene (hydrophobic) were used. Amphiphilic block copolymer conetworks were prepared by RAFT via the cross-linking of linear triblock copolymer precursors possessing two active polymer ends, which were subsequently interconnected by chemical cross-linking to a three-dimensional network, by using the appropriate cross-linker: ethylene glycol dimethacrylate for methacrylates, ethylene glycol diacrylate for acrylates, and 1,4-divinylbenzene for styrenics. The homopolymer and copolymer precursors to the (co)networks were characterized by gel permeation chromatography and 1 H NMR spectroscopy for their molecular weights and compositions, respectively. The degrees of swelling (DSs) of all (co)networks were determined in tetrahydrofuran and, where the ionizable (DMAEMA) was present, the DSs were also measured in neutral and acidic water. The conetworks swelled more in acidic than in neutral water due to the ionization of their DMAEMA units.

Living Radical Polymerization by the RAFT Process - A Second Update

“…The use of the corresponding trithiocarbonates 118-125 has also been promoted in this context. [27] Secondary aromatic dithioesters with R = -CHPh(CN) (42) and -CHPh(CO 2 R) (43)(44)(45)(46)(47)(48) and analogous trithiocarbonates 144, 145, and 146-148, respectively, have been shown to have utility in controlling 'R'-connected 79* [227] S S S S NIPAM [240] S S S S 80* [86,241,242] BMA [243] DMAEMA [240][241][242][243] AA [241] BA [243] St [241,243] DMAEMA-b-BMA [243] DMAEMA-b-BA [243] DMAEMA-b-St [243] St-b-HEMA/DMAEMA [86] 81 [244] CN S S…”

“…Polymer networks can be formed by crosslinking RAFTsynthesized homopolymers, block copolymers, [95,243,370] or star polymers [267] or can be formed directly by a RAFT (co)polymerization in te presence of crosslinking monomer (e.g., a divinyl monomer, ethylene glycol dimethacrylate, methylene-bis-acrylamide). [544,545] A wide variety of crosslinking processes have been explored.…”

Reaction Behavior and Network Development in RAFT Radical Polymerization of Dimethacrylates

“…[14,15,[25][26][27][28][29] In this work, we report experimental results on the RAFT polymerization of dimethacrylates. The reaction behavior and the evolution of the network microstructure in the RAFT system and its FRP counterpart were compared in order to understand the relationship between the kinetics and network structural development.…”

Photo-controlled/living radical polymerization of 2-(dimethylamino)ethyl methacrylate using 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl as a mediator

“…Amphiphilic block copolymers containing PDMAEMA are also used as stabilizers in dispersion polymerizations [11]. PDMAEMA has been prepared by various controlled manners, such as the living anionic polymerization [12][13][14], group transfer polymerization [15,16], atom transfer radical polymerization [17][18][19], reversible addition-fragmentation chain transfer polymerization [10,20], and thermal nitroxidemediated polymerization [21]. By using these polymerization techniques, a variety of amphiphilic copolymers of PDMAEMA has been created [22][23][24].…”