Multicompartment Microparticles with Patchy Topography through Solvent-Adsorption Annealing

Abstract

We report on the evaporation-induced confinement assembly (EICA) of polystyrene-b-polybutadiene-b-poly­(methyl methacrylate) (PS-b-PB-b-PMMA, SBM) triblock terpolymers into multicompartment microparticles and follow their morphological evolution during solvent-adsorption annealing. We initially obtain elliptic microparticles with axially stacked PS/PB/PMMA morphology using cetyltrimethylammonium bromide (CTAB) as surfactant. Exchanging the surfactant to poly­(vinyl alcohol) (PVA) during solvent vapor annealing with chloroform (CHCl3), PMMA preferentially interacts with the interface, and microparticles change their shape into spheres with concentric morphology. Surprisingly, this transformation initiates at both poles of the microparticles simultaneously and then proceeds toward the equator, resulting in particles with inner morphology and patchy topography. We observed this evolution for different PB fractions, suggesting the mechanism to be more general and the EICA process to be a suitable method to generate patchy particle surfaces.

A 3D Hierarchical Host with Enhanced Sodiophilicity Enabling Anode‐Free Sodium‐Metal Batteries

“…The BCP particles were generated through solvent-evaporative chloroform-in-water emulsions. [42,[48][49][50][51][52][53][54][55] In brief, poly(styrene-block-dimethylsiloxane) (PS-b-PDMS, number-average molecular weight (M n ) = 33 kg mol -1 ) BCP particles containing poly(styrene-random-poly vinylbenzylazide) (P(S-r-N 3 ), M n = 2 kg mol -1 ) polymers were generated. The use of SPG membrane emulsification affords the generation of uniformly-sized BCP particles (size ≈ 950 nm).…”

Size‐Controlled Formation of Polymer Janus Discs

“…The PS, PB and PMMA microphases alternate in form of an axially stacked lamellar structure due to their equal‐sized block compositions (S 32 B 40 M 28 202K ) as well as the comparable affinity for PS ( δ =18.5 MPa 1/2 ) and PMMA ( δ =19.0 MPa 1/2 ) to the SDS/water interface [42] . In TEM (Figure 1 d–f), the three microphases can be clearly identified: PS appears grey, PB dark due to osmium tetroxide (OsO 4 ) staining, and PMMA bright; the PMMA lamella appears thinner in TEM due to its degradation under the e ‐beam [43] . Grey scale analysis (Figure S3) revealed that the lamella thickness ( T = L 0 /2, Table 1) were 0.037 μm, 0.049 μm, and 0.052 μm for d pore =0.3 μm, 0.8 μm, and 2.0 μm, respectively.…”

“…[42] In TEM (Figure 1 d-f), the three microphases can be clearly identified: PS appears grey, PB dark due to osmium tetroxide (OsO 4 ) staining, and PMMA bright; the PMMA lamella appears thinner in TEM due to its degradation under the ebeam. [43] Grey scale analysis (Figure S3) revealed that the lamella thickness (T = L 0 /2, Table 1) were 0.037 mm, 0.049 mm, and 0.052 mm for d pore = 0.3 mm, 0.8 mm, and 2.0 mm, respectively. It is reasonable that the lamella thickness increased with larger membrane pore diameter.…”

Responsive Nanostructured Polymer Particles

“…For example, a mixture of CTAB and poly(vinyl alcohol) (PVA) provides a neutral interaction for PS- b -PI- b -P2VP triBCPs (PI: polyisoprene), affording the formation of prolate shape [ 43 ]. Confinement assembly of ABC triblock terpolymers has been further reported by varying the type of each block: PS- b -PB- b -PMMA, PS- b -PB- b -PtBMA, and PS- b -P4VP- b -PtBMA (PMMA: poly(methyl methacrylate), PtBMA: poly(t-butyl methacrylate)) [ 44 , 51 ]. Under spherical confinement stabilized by CTAB, the PS- b -PB- b -PtBMA triblock terpolymer adopts a hemispherical shape with a mixture of concentric lamella–axial lamella morphology [ 44 ].…”