One‐Shot Intrablock Cross‐Linking of Linear Diblock Copolymer to Realize Janus‐Shaped Single‐Chain Nanoparticles

Abstract

Developing an efficient and versatile process to transform as ingle linear polymer chain into as hape-defined nanoobject is am ajor challenge in the fields of chemistry and nanotechnology to replicate sophisticated biological functions of proteins and nucleic acids in asynthetic polymer system. In this study,w ep erformed one-shot intrablockc ross-linking of linear blockc opolymers (BCPs) to realizes ingle-chain nanoparticles (SCNPs) with two chemically compartmentalized domains (Janus-shaped SCNPs). Detailed structural characterizations of the Janus-shaped SCNP composed of polystyreneblock-poly(glycolic acid) revealed its compactly folded conformation and compartmentalized blockl ocalization, similar to the self-folded tertiary structures of natural proteins. Versatility of the one-shot intrablockc ross-linking was demonstrated using several different BCP precursors.I na ddition, the Janus-shaped SCNP produce miniscule microphase-separated structures.

A method to estimate the size of single-chain nanoparticles under severe crowding conditions

“…Eqn (9) is obtained from the well-known dependence of the domain spacing ( d ) on molecular weight ( M ) such as: 28 d ∼ M 2/3 . From the reported data by Watanabe et al 27 – as determined by size exclusion chromatography – ( = 23.8 kDa and M * = 11.7 kDa) we obtain d / d 0 ≈ 0.62 from eqn (9) and hence d = 14.9 nm, which is a value close to the experimental value (see Fig. 3 ).…”

“…We hypothesize here that the astonishing conformational behaviour of SCNPs under severe crowding conditions could contribute, to some extent, to this behaviour. Based on the size of the Janus-shaped SCNPs at high dilution determined by Watanabe et al 27 ( R 0 = 2.2 nm) we estimate R FG = 1.83 nm from eqn (4) as the size of these Janus-shaped SCNPs in the bulk state (a reduction of 27% when compared to the estimated size of the precursor block copolymer in the bulk state).…”

“…Very recently, Janus-shaped SCNPs have been proposed by Watanabe et al 27 as valuable nanomaterials for potential applications in ultrahigh resolution block copolymer lithography. Functionalized block copolymers composed of mutually immiscible PS and poly(glycolic acid) (PGA) blocks (PS- b -PGA) were subjected to one-shot intra-block cross-linking by these authors giving to compartmentalized Janus-shaped SCNPs with excellent self-assembling behaviour as determined by small-angle X-ray scattering (SAXS) measurements.…”

“…Interestingly, the microphase-separated structure of Janus-shaped SCNPs in the bulk state was found to be up to 47% smaller (domain spacing d = 12.7 nm) than that of the precursor block copolymer ( d 0 = 24.0 nm). 27 …”

Fabrication of Ultrafine, Highly Ordered Nanostructures Using Carbohydrate-Inorganic Hybrid Block Copolymers

“…Thus far, silicon-containing [ 3 , 5 , 6 , 7 , 10 , 12 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], metal-doped [ 31 , 32 , 33 ], and oligosaccharide-based BCPs [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ] have been developed. The high χ /low N BCP strategy is now widely accepted as a standard method for obtaining smaller d , although several novel approaches have emerged recently [ 19 , 34 , 35 , 40 , 49 , 50 , 51 , 52 , 53 , ...…”