Skip to content
PaperFren

Polymers

Watching RAFT PISA grow spheres, worms, vesicles

Czajka A, Armes SP · Chemical science · 2020

Open access · cc by · source: Europe PMC

In situ SAXS shows PGMA45-PHPMA200 aqueous RAFT PISA nucleating in 9–10 min and finishing as ~227 nm vesicles.

Study at a glance

Design
Other — In situ SAXS of aqueous RAFT HPMA polymerization from a PGMA45 macro-CTA
N
~2 mL SAXS cell polymerization tracking — no sample N
Population
Aqueous RAFT polymerization forming micelles, worms, and vesicles
Outcome
Time-resolved nucleation and morphological transitions during polymerization

Structured fields used in claim comparison tables when every cited study has a complete layer.

Key findings

Micelles nucleate at 9–10 min; worms appear near PHPMA DP 134 after 28–29 min; vesicles reach Dv = 227 ± 16 nm. HPMA conversion exceeds 99% within 80 min; GPC Mn is 51 200 g mol−1 with Đ = 1.25.

Methodology

Authors polymerized HPMA from a PGMA45 macro-CTA at 70 °C in a ~2 mL SAXS cell and tracked scattering while checking conversion, GPC, DLS, and TEM after the run.

Limitations

The SAXS nucleation clock is faster than the lab 1H NMR rate jump; other PISA monomers and concentrations are not mapped at the same time resolution.

How this study connects

Role on claims

Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.

  • SupportsPolymersconcept

    This library holds 5 empirical chemistry papers on polymers with isolated findings, rates or spectra rather than reviews.

    Evidence for the claim as stated.

  • SupportsPolymersconcept

    In situ SAXS shows PGMA45-PHPMA200 aqueous RAFT PISA nucleating in 9–10 min and finishing as ~227 nm vesicles.

    Evidence for the claim as stated.

  • After a ~2 mL in situ SAXS PISA run, TEM is the morphology check, not the nucleation clock. Micelles nucleate at 9–10 min by SAXS; worms appear near PHPMA DP 134 after 28–29 min; vesicles reach Dv = 227 ± 16 nm. HPMA conversion exceeds 99% within 80 min (GPC Mn 51 200 g mol⁻¹, Đ = 1.25). The SAXS clock is faster than the lab ¹H NMR rate jump.

    Evidence for the claim as stated.

  • A TEM image of the as-made solid can be characterisation while the mechanism lives elsewhere. Pyrite mesocrystal cubes (40–50 nm, SAED nearly single-crystalline) reconstruct into amorphous (oxy)hydroxide under OER CVs; SAXS, not TEM, clocks PISA nucleation at 9–10 min. Treating the first image as the operating structure is the disagreement between those papers and a simple 'TEM showed the catalyst/morphology' sentence.

    Evidence for the claim as stated.

Open questions

Tensions this paper is part of

From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.

  • Scope difference — different assays, populations, or outcomes

    A TEM image of the as-made solid can be characterisation while the mechanism lives elsewhere. Pyrite mesocrystal cubes (40–50 nm, SAED nearly single-crystalline) reconstruct into amorphous (oxy)hydroxide under OER CVs; SAXS, not TEM, clocks PISA nucleation at 9–10 min. Treating the first image as the operating structure is the disagreement between those papers and a simple 'TEM showed the catalyst/morphology' sentence.

Related papers in this topic

Same topic cluster — not a recommendation engine.