mz9b00711_si_001.pdf (1.11 MB)
Evolution of Single Chain Conformation for Model Comb-Like Chains with Grafting Density Ranging from 0 to ∼100% in Dilute Solution
journal contribution
posted on 2019-11-11, 19:33 authored by Xuejun Pan, Muhammad Waqas Ishaq, Ahmad Umair, Muhammad Waqas Ali, Lianwei LiThis work aims to experimentally
clarify how the single chain conformation
evolves as a function of grafting density for model comb-like chains
in dilute solution in the whole density regime. Via a combination
of rational design, precise synthesis and accurate characterization,
we obtained four sets of PPANb-g-PS30-σ comb-like samples with well-defined
architectures and accurately extracted their molecular parameters
by triple detection size exclusion chromatography (TD-SEC). With these
samples in hand, we quantified how the excluded volume interaction
and chain conformation evolve with the grafting density (σ)
in the whole density regime. Three main findings are reported: (i)
the graft–graft excluded volume interaction is not ignorable
even in the low σ-regime; (ii) contrary to theoretical predictions,
both the excluded volume interaction and the chain conformation are
found to be Nb-dependent; (iii) both Rg ∼ σ1/3 and [η]
∼ σ0 are experimentally confirmed for comb-like
chains from different σ and Nb,
signifying a unique 3D mass-size growth pattern and a quasi-3D fractal
feature. The obtained results help clarify some long-existed controversial
issues in the field.