Self-assembly Of ABC Triblock Copolymers Research Articles

Compartmentalization of an ABC triblock copolymer single-chain nanoparticle via coordination-driven orthogonal self-assembly

We present coordination-driven intramolecular orthogonal self-assembly of ABC triblock copolymer into protein-like compartmentalized SCNP, whose sub-10 nm ultrafine subdomains are discrete and can respond to aqueous surroundings individually.

Self-assembly of ABC triblock copolymers under 3D soft confinement: a Monte Carlo study.

Under three-dimensional (3D) soft confinement, block copolymers can self-assemble into unique nanostructures that cannot be fabricated in an un-confined space. Linear ABC triblock copolymers containing three chemically distinct polymer blocks possess relatively complex chain architecture, which can be a promising candidate for the 3D confined self-assembly. In the current study, the Monte Carlo technique was applied in a lattice model to study the self-assembly of ABC triblock copolymers under 3D soft confinement, which corresponds to the self-assembly of block copolymers confined in emulsion droplets. We demonstrated how to create various nanostructures by tuning the symmetry of ABC triblock copolymers, the incompatibilities between different block types, and solvent properties. Besides common pupa-like and bud-like nanostructures, our simulations predicted various unique self-assembled nanostructures, including a striped-pattern nanoparticle with intertwined A-cages and C-cages, a pyramid-like nanoparticle with four Janus B-C lamellae adhered onto its four surfaces, an ellipsoidal nanoparticle with a dumbbell-like A-core and two Janus B-C lamellae and a Janus B-C ring surrounding the A-core, a spherical nanoparticle with a A-core and a helical Janus B-C stripe around the A-core, a cubic nanoparticle with a cube-shape A-core and six Janus B-C lamellae adhered onto the surfaces of the A-cube, and a spherical nanoparticle with helical A, B and C structures, from the 3D confined self-assembly of ABC triblock copolymers. Moreover, the formation mechanisms of some typical nanostructures were also examined by the variations of the contact numbers with time and a series of snapshots at different Monte Carlo times. It is found that ABC triblock copolymers usually aggregate into a loose aggregate at first, and then the microphase separation between A, B and C blocks occurs, resulting in the formation of various nanostructures.

Polymerization-Induced Self-Assembly of ABC Triblock Copolymer

Polymerization-Induced Self-Assembly of ABC Triblock Copolymer

Influence of nucleobase stoichiometry on the self-assembly of ABC triblock copolymers.

ABC triblock copolymers bearing adenine- and thymine-functionalized external blocks self-assembled into long-range, ordered lamellar microphase-separated morphologies on non-patterned substrates. Intermolecular hydrogen bonding formed thymine-adenine triplets and promoted self-assembly into well-defined lamellae consisting of poly(n-butyl acrylate) soft domains and complementary nucleobase hard domains, while thymine-adenine duplets contributed to superior mechanical properties.

Effect of shear flow on the self-assembly of ABC triblock copolymers in selective solvent

We have studied the effect of shear flow on the self-assembly of ABC amphiphilic copolymers in dilute selective solutions by changing the stirring rate and the composition of the triblock copolymer. The results revealed that the self-assembled morphology strongly depends on the stirring rate and the composition of the copolymer. The self-assembled morphology formed by the ABC triblock copolymer in selective solvent is the result in a competition between the shear flow and the interfacial tension of the micelles.

Comprehensive Phase Behavior of Poly(isoprene-b-styrene-b-ethylene oxide) Triblock Copolymers

The phase behavior of 44 poly(isoprene-b-styrene-b-ethylene oxide) (ISO) linear triblock copolymer melts was investigated at weak to intermediate segregation strengths and spanning a comprehensive range of compositions. Phases were characterized by a combination of experimental techniques, including small-angle X-ray scattering, dynamic mechanical spectroscopy, transmission electron microscopy, and birefringence measurements. Combined with our previous results, six different stable ordered state symmetries have been identified: lamellae (LAM), Fddd orthorhombic network (O70), double gyroid (Q230), alternating gyroid (Q214), hexagonal (HEX), and body-centered cubic (BCC). The phase map of ISO specimens was found to be somewhat asymmetric around the fI = fO isopleth. This work provides a guide for theoretical studies and gives insight into the intricate effects of various parameters on the self-assembly of ABC triblock copolymers. Experimental SAXS data evaluated with a simple scattering intensity model sh...

Self-Assembly of ABC Triblock Copolymer into Giant Segmented Wormlike Micelles in Dilute Solution

We report the self-assembly of a linear ABC triblock copolymer into the previously unknown architecture of giant segmented wormlike micelles (SWMs). The lengths and diameters of these giant SWMs were as high as ca. 10 μm and 500 nm, respectively. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analysis revealed that the SWMs comprised sequences of repeated elemental parts, i.e., disks having a thickness of ca. 65 nm. A most interesting feature is that disks having different diameters became connected through threads to form various giant segmented wormlike micelles. A kinetic study indicated that the process of SWM formation occurred basically through three stages: (1) the ABC triblock copolymer self-assembled into small spheres of ca. 38 nm diameter; (2) these small spheres joined together to form intermediate shuttlelike structures; (3) the spheres within the shuttlelike structures rearranged and underwent further adjustment to form the final SWMs.

A molecular dynamics simulation on the self-assembly of ABC triblock copolymers. 3. Effects of block composition in asymmetric triblock copolymers

The self-assembly of asymmetric ABC triblock copolymers in the ordered structure is investigated using an isothermal-isobaric molecular dynamics simulation. Unlike symmetric ABC triblock copolymers, more fascinating morphologies are observed in asymmetric ones because of a larger difference of incompatibility between the components. Various modes of self-assembly in assymmetric ABC triblock copolymers are also observed depending on the block composition. When the composition of block A is changed from 0.125 to 0.25 at the samef B =0.25, the morphological transition from the “cylinder in cylinder” to “cylinders at cylinder” structure is observed in the simulation. In the case of ABC triblocks withf B =0.5, a lamellar-type structure is changed to a cylinder-type structure with increasing the length of block A. When the mid-block length increases further tof B =0.625, the “spheres on cylinder” structure is observed in both the A10B50C20 and A20B50C10 triblocks. From these results, the phase diagram of ABC triblock copolymers can be constructed.

A molecular dynamics simulation on the self-assembly of ABC triblock copolymers. 2. Effects of block sequence

The effect of block sequence on the self-assembly of ABC-type triblock copolymers in the ordered state is investigated using an isothermal-isobaric molecular dynamics simulation. The block sequence has an important effect on the morphology of ABC triblock copolymers. Different morphologies are observed depending on the block sequence as well as the block composition. The triblock copolymers with the volume fraction of 1:1:1 (f A=f B=f C=0.33) show the three phase and four layered lamellar structures irrespective of the block sequence. The A32B16C32 triblock copolymer withf B=0.2 shows a morphology in which cylinders of midblock B are formed at the interface between A and C lamellae, whereas the morphology of triblock copolymer B16C32A32 and C32A32B16 show a cylindrical core-shell structure and a lamellar type morphology, respectively. The A20B40C20 triblock copolymer with the block B as a major component shows a tricontinuous structure, whereas both B40C20A20 and C20A20B40 triblock copolymers exhibit the lamellar structures. When the block B has larger volume fraction withf B=0.75, the matrix is composed of block B, and other two blocks A and C form spherical domains.

A Molecular Dynamics Simulation on the Self-Assembly of ABC Triblock Copolymers, 1. Effects of Block Composition in Symmetric Triblock Copolymers

The self-assembly of ABC triblock copolymers in the microphase-separated state is investigated using an isothermal-isobaric molecular dynamics simulation. For the validation of our simulation scheme, ABA triblock copolymers are also simulated. We examine the effect of the composition (f B ) of symmetric triblock copolymers on the morphology realized in these copolymers, keeping other parameters fixed. For ABA triblock copolymers, the transition from lamellar to cylindrical morphologies is observed with increasing the composition from f B = 0.5 to f B = 0.75, and such behavior is supported by calculation results of scattering putterns. These simulated results agree well with experimental and theorotical ones, validating our simulation method. More complex structures are predicted for ABC triblock copolymers. If midblock B is the minor component, its structures are changed from lamellar, cylindrical, to spherical morphology at the interface between A/C lamellae as f B decreases. For ABC triblock copolymers with the mldblock B as the major component, the morphology of end blocks in the matrix composed of the midblock is changed from tricontinuous to spherical structures as f B increases.