Research on block copolymers (BCPs) has played a critical role in the development of polymer chemistry, with numerous pivotal contributions that have advanced our ability to prepare, characterize, theoretically model, and technologically exploit this class of materials in a myriad of ways in the fields of chemistry, physics, material sciences, and biological and medical sciences. The breathtaking progress has been driven by the advancement in experimental techniques enabling the synthesis and characterization of a wide range of block copolymers with tailored composition, architectures, and properties. In this review, we briefly discussed the recent progress in BCP synthesis, followed by a discussion of the fundamentals of self-assembly of BCPs along with their applications.
The room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, [C4mim][PF6] was found to be an efficient plasticizer for poly(methyl methacrylate), prepared by in situ radical polymerization in the ionic liquid medium; the polymers have physical characteristics comparable with those containing traditional plasticizers and retain greater thermal stability.
Free-radical polymerization of methyl methacrylate and styrene using conventional organic initiators in the room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) is rapid and produces polymers with molecular weights up to 10× higher than from benzene; both polymerization and isolation of products were achieved without using VOCs, offering economic as well as environmental advantages.
This article reviews current experimental observations and theoretical calculations devoted towards understanding micro-phase separation in charged block copolymer systems. We discuss bulk morphologies in melt and in solution, as well as some of the new emerging research directions. Overall, a comprehensive picture is beginning to emerge on the fundamental role of electrostatics in the micro-phase separation of charged block copolymers. This understanding provides exciting new insight that may be used to direct targeted structures that endow the materials with desired properties that can have tremendous potential in technological applications.
All acrylic-based thermoplastic elastomers (TPEs) offer potential alternatives to the widely-used styrenic TPEs. However, the high entanglement molecular weight (Me) of polyacrylates, as compared to polydienes, leads to “disappointing” mechanical performance as compared to styrenic TPEs. In this study, triblock copolymers composed of alkyl acrylates with different pendant groups and different glass transition temperatures (Tgs), i.e. 1-adamatyl acrylate (AdA) and tetrahydrofurfuryl acrylate (THFA), were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. Thermal characterization of the resulting polymers was performed using differential scanning calorimetry (DSC), and the Tgs of both segments were observed for the block copolymers. This indication of microphase separation behavior was further demonstrated using atomic-force microscopy (AFM) and small angle X-ray scattering (SAXS). Dynamic mechanical analysis (DMA) showed that the softening temperature of the PAdA domains is 123 °C, which is higher than that of both styrenic TPEs and commercial acrylic based TPEs with poly(methyl methacrylate) (PMMA) hard block. The resulting triblock copolymers also exhibited stress–strain behavior superior to that of conventional all acrylic-based TPEs composed of PMMA and poly(n-butyl acrylate) (PBA) made by controlled radical processes, while the tensile strength was lower than for products made by living anionic polymerization.
Well-defined acryloyl β-alanine (ABA) polymers were synthesized directly via atom transfer radical polymerization (ATRP) under near physiological conditions using various water soluble initiators with high yield and narrow molecular weight distributions.