Here we report the synthesis and characterization of block copolymer/layered silicate (BCPLS) nanocomposites via the surface-initiated ring-opening metathesis polymerization (SI-ROMP) of norbornene and cyclopentene from montmorillonite clay (MMT). The MMT particle surfaces were functionalized with a norbornene-terminated alkylammonium surfactant through ion exchange. Block copolymer brushes of norbornene and cyclopentene were polymerized directly from the surface of these functionalized clay platelets, yielding highly exfoliated nanocomposites. A fraction of the polymer brushes were removed from their substrate by reverse ion exchange and characterized in parallel with their corresponding nanocomposite analogues. The thermal, mechanical, and morphological characteristics of the BCPLSs and their neat analogues were then compared directly. This enabled us to assess the role of the MMT filler in the thermal properties, solid/melt state rheology, and morphology. Disciplines Polymer Science CommentsReprinted with permission from Macromolecules 46 (2013) ABSTRACT: Here we report the synthesis and characterization of block copolymer/layered silicate (BCPLS) nanocomposites via the surface-initiated ring-opening metathesis polymerization (SI-ROMP) of norbornene and cyclopentene from montmorillonite clay (MMT). The MMT particle surfaces were functionalized with a norbornene-terminated alkylammonium surfactant through ion exchange. Block copolymer brushes of norbornene and cyclopentene were polymerized directly from the surface of these functionalized clay platelets, yielding highly exfoliated nanocomposites. A fraction of the polymer brushes were removed from their substrate by reverse ion exchange and characterized in parallel with their corresponding nanocomposite analogues. The thermal, mechanical, and morphological characteristics of the BCPLSs and their neat analogues were then compared directly. This enabled us to assess the role of the MMT filler in the thermal properties, solid/melt state rheology, and morphology.

The development of hydrogel-based molecularly imprinted polymer (HydroMIPs) technology for the memory imprinting of proteins and for protein biosensor development presents many possibilities, including uses in bio-sample clean-up or selective extraction, replacement of biological antibodies in immunoassays and biosensors for medicine and the environment. Biosensors for proteins and viruses are currently expensive to develop because they require the use of expensive antibodies. Because of their biomimicry capabilities (and their potential to act as synthetic antibodies), HydroMIPs potentially offer a route to the development of new low-cost biosensors. Herein, a metal ion-mediated imprinting approach was employed to metal-code our hydrogel-based MIPs for the selective recognition of bovine serum albumin (BSA). Specifically, Co(II)-complex based MIPs exhibited a 66% enhancement (in comparison to our normal MIPs) exhibiting 92 ± 1% specific binding with Q values of 5.7 ± 0.45 mg BSA/g polymer and imprinting factors (IF) of 14.8 ± 1.9 (MIP/ non-imprinted (NIP) control). The proposed metal-coded MIPs for protein recognition are intended to lead to unprecedented improvement in MIP selectivity and for future biosensor development that rely on an electrochemical redox processes.

Here we report microphase-separated poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) as a reinforcing filler in PDMS thermosets that overcomes the long-standing problem of aging in the processing of silicareinforced silicone. Surprisingly, PS-b-PDMS reinforced composites display comparable mechanical performance to silica-modified analogs, even though the modulus of PS is much smaller than that of silica and there is no evidence of percolation with respect to the rigid PS domains. We have found that a few unique characteristics contribute to the reinforcing performance of PS-b-PDMS. The strong selfassembly behavior promotes batch-to-batch repeatability by having well-dispersed fillers. The structure and size of the fillers depend on the loading and characteristics of both filler and matrix, along with the shear effect. The reinforcing effect of PS-b-PDMS is mostly brought by the entanglements between the corona layer of the filler and the matrix, rather than the hydrodynamic reinforcement of the PS phase.

In this work, methacrylate polymers with different thermal and viscoelastic properties were synthesized from red oak lignin bio-oil. The bio-oil, also called pyrolytic lignin (PL), consisted of various phenolic monomers and oligomers with average hydroxyl content of 3.04 mol/mol. The PL was first esterified with different amounts of methacryloyl chloride and acetyl chloride to form PL methacrylates and then subjected to reversible addition–fragmentation chain transfer polymerization. Polymerization of fully methacrylated PL caused gelation to yield a cross-linked polymer. On the other hand, gel-point suppression occurred in the polymerization of partially methacrylated PL to yield a thermoplastic polymer with glass transition temperature (T g) of 161 °C and thermal decomposition temperature (T d) of 241 °C. In comparison, the functionalization of PL by partial methacrylation and subsequent acetylation resulted in a polymer with T g of 130 °C and T d of 250 °C. Unlike other biobased methacrylate polymers that cannot withstand high temperatures and volatilize, the polymers produced from this study retained 25–28% mass when pyrolyzed to 1000 °C. The latter polymer was also melt-spinnable and demonstrated highly attractive properties as an ideal carbon fiber precursor. Other than its narrow molecular weight distribution and high isothermal stability, this lignin-based polymer also had a linear molecular orientation that is critical in producing high-quality carbon fiber.

Here we report the phase behavior of a family of montmorillonite (MMT) block copolymer brushes (MBBs), a novel class of polymer nanocomposites. MBBs are comprised of discrete MMT platelets encapsulated with block copolymer brushes. These MBBs were synthesized via surface-initiated atom transfer radical polymerization using halogenated alkylammonium surfactants to localize initiation sites on the clay surfaces. Two styreninc MBB systems-poly(styrene-b-n-butyl acrylate) and poly(styrene-b-t-butyl acrylate)-were prepared varying the composition and total M n 5 80-250 kDa. MBB materials were compared with their non-clay bulk block copolymer counterparts via electron microscopy and a host of mechanical tests in both the solid and melt states. Notably, MBBs have similar melt-state rheological properties compared to neat block copolymers and are thus amenable to current processing techniques. MBBs were found to self-assemble into single grain morphologies across incredibly large areas (>3 lm) which resulted in extremely well-ordered, defect-free lamellar structures with applications in microelectronics.