Soft Character of Star-Like Polymer Melts: From Linear-Like Chains to Impenetrable Nanoparticles

Abstract

The importance of microscopic details in the description of the behavior of polymeric nanostructured systems, such as hairy nanoparticles, has been lately discussed via experimental and theoretical approaches. Here we focus on star polymers, which represent well-defined soft nano-objects. By means of atomistic molecular dynamics simulations, we provide a quantitative study about the effect of chemistry on the penetrability of star polymers in a melt, which cannot be considered by generic coarse-grained models. The “effective softness” estimated for two dissimilar polymers is confronted with available literature data. A consistent picture about the star penetrability can be drawn when the star internal packing is taken into consideration besides the number and the length of the star arms. These findings, together with the recently introduced two-layer model, represent a step forward in providing a fundamental understanding of the soft character of stars and guiding their design toward advanced applications, such as in all-polymer nanocomposites.

Unified Understanding of the Structure, Thermodynamics, and Diffusion of Single-Chain Nanoparticle Fluids

“…Since the central feature of the theories is that they relate the internal structure of a soft nanoparticle to its real space intermolecular packing, collective structure, thermodynamics, and dynamics, it can potentially be adapted to treat other compact soft nanoparticle systems. For example, highly branched star polymers, ,, nano- and micro-gels, , micelles, different types of glycogens, perhaps even folded proteins, ,, and dense liquids of two-dimensional polymer chains, all of which are globally compact but with distinct internal conformational structure at the segmental level.…”

On Uniformly Starlike Functions with Respect to Symmetrical Points Involving the Mittag-Leffler Function and the Lambert Series

“…This domain is created by joining the fixed point to every other point in the domain using straight-line segments. While starlike functions are utilized in geometric function theory and mathematical physics to simulate phenomena like electrostatics [1,2] and fluid flow [3,4], univalent functions are frequently used in geometric function theory to explore conformal mappings and the Riemann mapping theorem.…”

“…τ(3) 2 C(C − 2) + τ(2)τ(4) .One can simply show that∂Y(ρ,C) ∂ρ> 0 for ρ > 0, hence, Y(ρ, C) is an increasing function and, thus, the upper bound for Y(ρ, C) corresponds to ρ = 1 andmaxY(ρ) = Y(1, C) = G(C), C 4 N + M + τ(3) 2 P 2 1 − τ(2)τ(4)P 2 (C) = −τ(2)τ(4)S 2 −2τ(2)τ(4)P 1 S] 16τ(2)τ(4)τ(3) C 2 M + 2P 2 1 τ(3) 2 − 2τ(2)τ(4)P 1 S + −2τ(2)τ(4)] 16τ(2)τ(4)τ(3) 2 + [C 2 (4−C 2 )P 2 1 τ(3) 2 +(4−C 2 )τ(2)τ(4)P 2 2C[4M+12P 2 1 τ(3) 2 −(8P 1 S−9P21 )τ(2)τ(4)] 16τ(2)τ(4)τ(3) 2…”

The Extreme of Disentanglement: 100-fold Viscosity Reduction in Model Single-Chain Nanoparticles

“…SCNPs bridge the polymeric and colloidal domains. The boundary between polymers and colloids is not trivial to define, except for some pioneering works. − Multiarm star polymers with an exceptionally high number of arms have been extensively studied to understand the transition from polymers to colloids. , Microemulsion polymerization has long been used for the production of soft nanoparticles and has recently gained increasing attention. − In their melt state, we have identified two types of viscoelasticity controlled by the radius and elasticity (cross-linking degree N cr , the average number of repeating units between adjacent cross-linking points) of the sample, both exhibiting an elastic plateau: one with a finite relaxation time and the other with an immeasurably long relaxation time . The latter falls in the colloid domain (where the relaxation time does not depend on temperature).…”