Nucleobase-Containing Block Copolymers Having a High Interaction Parameter by Complementary Hydrogen Bonding

Abstract

Nucleobase-containing block copolymers have received great attention due to their strong complementary multiple hydrogen bonding and potential applications for biosensors and biochemical catalysis. To improve the sensing and catalytic performance, the feature size should be minimized. In this study, we synthesized, via reversible addition–fragmentation chain transfer polymerization, the poly­[9-(4-vinylbenzyl)­adenine]-ran-poly­[1-(4-vinylbenzyl)­thymine]-block-polystyrene copolymer {P­[VBA x -r-VBT(1–x)]-b-PS} by varying the volume ratio of 9-(4-vinylbenzyl)­adenine (VBA) to 1-(4-vinylbenzyl)­thymine (VBT) (x = 0, 0.25, 0.5, 0.75, and 1), while maintaining the volume fraction of the PS block close to 0.5. We found that the Flory–Huggins interaction parameter (χ) between P­[VBA x -r-VBT(1–x)] and PS was larger than χ between neat PVBA and PS as well as χ between neat PVBT and PS. χ becomes the maximum at x = 0.5. P­(VBA0.5-r-VBT0.5)-b-PS with a total molecular weight as small as 3300 g mol–1 showed well-defined lamellar microdomains with a domain spacing of 8.6 nm. On the other hand, both neat PVBA-b-PS and PVBT-b-PS with the same molecular weight as P­(VBA0.5-r-VBT0.5)-b-PS exhibited a disordered state. The increased χ between P­[VBA x -r-VBT(1–x)] and PS was attributed to the strong complementary hydrogen bonding between VBA and VBT, which was confirmed by Fourier-transform infrared spectroscopy.

Fabrication of High χ-Low N Block Copolymers with Thermally Stable Sub-5 nm Microdomains Using Polyzwitterion as a Constituent Block

“…The central point to design high χ-low N BCPs is to find two polymers with quite different physical and chemical properties like surface energy, hydrophily hydrophobicity, and so on. Based on this principle, polymers containing fluorine, − silicon, − hydroxyl or amino groups, ,− carbonate groups, and crystalline/liquid crystalline structures − are frequently used as the constituent block of high χ-low N BCPs. However, above-mentioned polymers usually involve complicated monomer synthesis or polymerization.…”

Chemically tailored block copolymers for highly reliable sub-10-nm patterns by directed self-assembly

“…The presence of hydroxy and trifluoroethyl groups in 10–30 mol% concentrations in PMMA seems to enhance the χ eff value significantly. This increase is likely due to enhanced interactions within the polymer blocks, similar to the observed self-interactions in PSVN- b -PMMA caused by vinylnaphthalene units 48 and complementary hydrogen bonding between adenine and thymine moieties in P(VBA- r -VBT)- b -PS 66 . In this study, hydrogen bonding by hydroxy groups introduced into the PMMA block increased intra-block interactions within PG F M. In addition, the χ eff values of A- b -(B- r -C) copolymers are estimated by ref.…”

Mesoporous Phenolic/POSS Hybrids Induced by Microphase Separation Arising from Competitive Hydrogen Bonding Interactions

“…The self-assembly of linear diblock copolymers in the bulk state, forming body-centered cubic (BCC), hexagonal-packing cylinder (HEX), double-gyroid (DG), and lamellae (LAM) structures, mediated by the interaction parameter (χ), volume fraction ( f ), and molecular weight ( N ), is being investigated widely because of their potential applications in nanopatterns, nanocomposites, drug delivery, and electronic and photonic devices. − Blending diblock copolymers with homopolymers, copolymers, nanoparticles, and organic–inorganic hybrids to vary the volume fractions and interaction parameters, mediated by hydrogen-bonding interactions, is another simple approach toward fabricating various self-assembled structures. − Recently, Frank–Kasper (FK) phases, including A15, σ, C14, and C15 phases, have also been observed in the phase diagrams of diblock copolymers through both experimental studies and theoretical predictions. − …”