Composition-Orientation Induced Mechanical Synergy in Nanoparticle Brushes with Grafted Gradient Copolymers.
Macromolecules
; 56(23): 9626-9635, 2023 Dec 12.
Article
em En
| MEDLINE
| ID: mdl-38105929
ABSTRACT
Gradient poly(methyl methacrylate/n-butyl acrylate) copolymers, P(MMA/BA), with various compositional ratios, were grafted from surface-modified silica nanoparticles (SiO2-g-PMMA-grad-PBA) via complete conversion surface-initiated activator regenerated by electron transfer (SI-ARGET) atom transfer radical polymerization (ATRP). Miniemulsion as the reaction medium effectively confined the interparticle brush coupling within micellar compartments, preventing macroscopic gelation and enabling complete conversion. Isolation of dispersed and gelled fractions revealed dispersed particle brushes to feature a higher Young's modulus, toughness, and ultimate strain compared with those of the "gel" counterparts. Upon purification, brush nanoparticles from the dispersed phase formed uniform microstructures. Uniaxial tension testing revealed a "mechanical synergy" for copolymers with MMA/BA = 32 molar ratio to concurrently exhibit higher toughness and stiffness. When compared with linear analogues of similar composition, the brush nanoparticles with gradient copolymers had better mechanical properties, attributed to the synergistic effects of the combination of composition and propagation orientation, highlighting the significance of architectural design for tethered brush layers of such hybrid materials.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Revista:
Macromolecules
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Estados Unidos