Small‐Angle X‐Ray Scattering Studies of Block Copolymer Nano‐Objects: Formation of Ordered Phases in Concentrated Solution During Polymerization‐Induced Self‐Assembly

Rymaruk, Matthew J.; O'Brien, Cate T.; György, Csilla; Darmau, Bastien; Jennings, James; Mykhaylyk, Oleksandr O.; Armes, Steven P.

doi:10.1002/anie.202101851

Cited by 20 publications

(14 citation statements)

References 95 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, fitting of the form factor is hardly possible, as the intensity in this region is overlapped with a weak (50) reflection. The pattern bears similarities with a system of the diluted cylinders, which can display at a certain dilution only orders of the fundamental Bragg peak.…”

Section: Resultsmentioning

confidence: 59%

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the AB_n and A_nB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

et al. 2021

View full text Add to dashboard Cite

Novel miktoarm star copolymers of polystyrene[poly(dimethylsiloxane) n ] or PS(PDMS) n (n = 2 or 3) type as well as of the inversed sequence, namely, (polystyrene) n [poly(dimethylsiloxane)] or (PS) n PDMS (n = 2 or 3), were synthesized by combining living anionic polymerization with chlorosilane chemistry. The miktoarm star copolymers were extensively characterized through size exclusion chromatography, vapor pressure/membrane osmometry, proton nuclear magnetic resonance, and differential scanning calorimetry, in order to verify the successful synthesis. All samples with varying volume fractions and narrow dispersity indices (D̵ < 1.1) were morphologically characterized by transmission electron microscopy and small-angle X-ray scattering, in order to study their self-assembly behavior as well as to examine the effect of the complex architecture on the final adopted morphologies. For specific PS(PDMS) n (n = 2 or 3), morphologies different from those expected from theoretical predictions (self-consistent field theory or Gaussian statistics) were obtained, while for the inversed sequences, namely, (PS) n PDMS (n = 2 or 3), no discrepancies were evident. This fact further confirmed the impact of the number of arms as well as the flexibility of the segments (PS being stiffer than PDMS) on the structure/property relationship.

show abstract

Section: Resultsmentioning

confidence: 59%

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the AB_n and A_nB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The soluble precursor block is typically either poly(lauryl methacrylate) ,,, or poly(stearyl methacrylate). − ,− , However, alternative examples include poly(2-ethylhexyl acrylate), , poly(lauryl acrylate), poly(behenyl methacrylate), or 3-[tris(trimethylsilyloxy)silyl] propyl methacrylate . In addition, monohydroxy-capped precursors such as polydimethylsiloxane or hydrogenated polybutadiene , can be converted into suitable macromolecular RAFT agents via esterification using a suitable carboxylic acid-functionalized RAFT agent. Similarly, various types of structure-directing insoluble blocks have been studied, including poly(benzyl methacrylate), − ,,− poly(benzyl acrylate), poly(3-phenylpropyl methacrylate), − poly(glycidyl methacrylate), , poly(2-hydroxypropyl methacrylate), poly(2,2,2-trifluoroethyl methacrylate), ,, or poly(2-(dimethylamino)ethyl methacrylate) …”

Section: Introductionmentioning

confidence: 99%

RAFT Dispersion Polymerization of Methyl Methacrylate in Mineral Oil: High Glass Transition Temperature of the Core-Forming Block Constrains the Evolution of Copolymer Morphology

et al. 2021

Self Cite

View full text Add to dashboard Cite

RAFT dispersion polymerization of a prototypical methacrylic monomer, methyl methacrylate (MMA), is performed in mineral oil using various poly(lauryl methacrylate) (PLMA) precursors prepared with a trithiocarbonate-based RAFT agent. GPC analysis indicated reasonably narrow molecular weight distributions (M w /M n ≤ 1.39) for all diblock copolymers, with 1 H NMR studies indicating high MMA conversions (≥95%) for all syntheses. An efficient one-pot synthesis protocol enabled high blocking efficiencies to be achieved when targeting higher PMMA DPs. However, the relatively high glass transition temperature (T g ) of the corresponding core-forming PMMA block unexpectedly constrains the evolution in copolymer morphology during polymerization-induced self-assembly (PISA). More specifically, well-defined PLMA 22 −PMMA x spheres (x = 19−39) and relatively short worms (x = 69−97) can be obtained at 90 °C when using a PLMA 22 precursor but targeting higher x values (x ≥ 108) invariably leads to colloidally unstable aggregates of spheres, rather than long worms or vesicles. Interestingly, similar constraints were observed when targeting higher solids, when using n-dodecane instead of mineral oil, or when employing an alternative steric stabilizer block. Raising the PISA synthesis temperature from 90 to 115 °C (i.e., from below to above the T g of the final PMMA block) does not alleviate this unexpected problem. Moreover, only spherical nanoparticles can be obtained at 115 °C when targeting PMMA DPs between 50 and 400 with the same PLMA 22 precursor. This suggests that nanoparticle formation may occur by a chain expulsion/insertion mechanism at this relatively high reaction temperature. PLMA 22 −PMMA x nanoparticles were characterized in terms of their particle size and morphology using dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). DLS and TEM studies of a 0.1% w/w dispersion of PLMA 22 −PMMA 69 short worms indicated an irreversible worm-to-sphere transition on heating from 20 to 150 °C. Oscillatory rheology and TEM studies indicated that this thermal transition was only partially reversible for a 20% w/w dispersion of PLMA 22 −PMMA 69 short worms.

show abstract

“…Bragg reflections expected in SAXS measurements of the ordered BCP solutions. [23,[92][93][94][95][96] Lattice type Bragg reflections (q/q * ) Simple cubic (SC) q * is the first/primary peak, appearing in the SAXS curve. (q/q * ) is the relative peak positions.…”

Section: The Formation Mechanism Of Snips Membranesmentioning

confidence: 99%

How does Micro‐ and Macro‐Phase Separation of Block Copolymers Affect the Formation of Integral Asymmetric Isoporous Membranes? A Review on Effective Factors

Foroutani

Ghasemi

2022

Macro Materials & Eng

View full text Add to dashboard Cite

Self-standing isoporous membranes based on amphiphilic block copolymers (BCPs) are an outstanding candidate for efficient separation processes. Such fascinating membranes have been generated through combining the BCP self-assembly (micro-phase separation) together with the classical non-solvent induced phase separation (macro-phase separation), known as SNIPS process. However, the controllability, reproducibility, and cost-effectiveness of the process along with the mechanism for pores generation are still challenging in the SNIPS strategy, especially when new BCP or conditions are utilized. It is mainly due to the narrow efficacy window of numerous variables influencing the desired structure formation. In this review, first, an overview of the one-step readily scalable SNIPS technique and the stepwise explanation of the process are given. Then the formation mechanism of SNIPS membranes, according to the related hypotheses and assumptions proposed on the basis of experimental evidence so far, is presented and discussed. As the main focus , governing factors in the SNIPS process which affect the preparation and structural characteristics of final membrane structures are entirely reviewed and interpreted. This review will help to have a better understanding of the connection between determinant factors and final membrane structure, which facilitates successful preparation of BCP membranes via SNIPS.

show abstract

Small‐Angle X‐Ray Scattering Studies of Block Copolymer Nano‐Objects: Formation of Ordered Phases in Concentrated Solution During Polymerization‐Induced Self‐Assembly

Cited by 20 publications

References 95 publications

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the AB_n and A_nB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the AB_n and A_nB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

RAFT Dispersion Polymerization of Methyl Methacrylate in Mineral Oil: High Glass Transition Temperature of the Core-Forming Block Constrains the Evolution of Copolymer Morphology

How does Micro‐ and Macro‐Phase Separation of Block Copolymers Affect the Formation of Integral Asymmetric Isoporous Membranes? A Review on Effective Factors

Contact Info

Product

Resources

About

Small‐Angle X‐Ray Scattering Studies of Block Copolymer Nano‐Objects: Formation of Ordered Phases in Concentrated Solution During Polymerization‐Induced Self‐Assembly

Cited by 20 publications

References 95 publications

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the ABn and AnB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the ABn and AnB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

RAFT Dispersion Polymerization of Methyl Methacrylate in Mineral Oil: High Glass Transition Temperature of the Core-Forming Block Constrains the Evolution of Copolymer Morphology

How does Micro‐ and Macro‐Phase Separation of Block Copolymers Affect the Formation of Integral Asymmetric Isoporous Membranes? A Review on Effective Factors

Contact Info

Product

Resources

About

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the AB_n and A_nB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)

Synthesis, Molecular Characterization, and Phase Behavior of Miktoarm Star Copolymers of the AB_n and A_nB (n = 2 or 3) Sequences, Where A Is Polystyrene and B Is Poly(dimethylsiloxane)