Broadband dielectric spectroscopy to validate architectural features in Type-A polymers: Revisiting the poly(glycidyl phenyl ether) case

Synthesis of Macrocyclic Poly(glycidyl phenyl ether) with an Inverted-Dipole Microstructure via Ring Closure of Two-Arm Linear Precursors Obtained by Initiation witht-BuP4/Water

“…We first need to recall that according to the Rouse model for unentangled polymers, only odd modes contribute to the end-to-end chain relaxation. For linear and regioregular chains, end-to-end chain motions cause dipole moment fluctuations that result in a dielectric relaxation with a main relaxation time , with p = 1. ,, However, for polymers composed of two symmetric inverted-dipole arms, the NM relaxation would be described by even modes. In this case, the main dielectric relaxation time is , with p = 2. , Consequently, the dielectric NM relaxation should be faster by a factor of 4 than the end-to-end vector fluctuation.…”

“…In the current study, we used T ref = T g,D . It is important to note that eqs and are mathematically equivalent, but they are applied for the analysis of different processes only for convenience. , In the current study, we used in the fittings τ 0 = 10 –14 s, D = 6.1, C 1 = 30, and C 2 = 34.8 K, as previously found in the dielectric analysis of the PGPE samples. , Note that the WLF equation is often expressed in terms of 10-based logarithm and in this case the value of C 1 would be modified by a factor log 10 e .…”

“…When a polymer presents dipole moments of the monomeric units (μ p ) parallel to the main chain, the resulting dipole moment along the chain contour ( ) is proportional to the end to end vector ( ) in a linear chain, . However, this is only true for regioregular linear chains where all the repeating units are oriented in the same direction, but not for polymers containing regioirregularities or dipolar inversions. − The fluctuations of the resulting dipole moment in an electric field result in a dielectric relaxation usually referred to as the normal mode (NM) . According to Stockmayer, this case refers to a type-A polymer …”

“…In its linear form, this polymer exhibits a NM relaxation. Here, we can distinguish between two types of dipolar microstructures for a linear chain . Linear chains with all monomers oriented in the same direction will be named as one-arm linear polymers (Scheme a) and those having two symmetric regioregular subchains with an opposite dipole moment orientation will be named inverted-dipole two-arm polymers (Scheme b).…”

Topical Issue on Dielectric Spectroscopy Applied to Soft Matter

“…This collection presents the investigation of different forms of soft matter via dielectric spectroscopy. Focusing on macromolecular systems, BDS has been employed, here, as an innovative tool to assess the outcome of polymer synthesis, by validating architectural features [1], to characterize with nanometric precision the spatially heterogeneous structure of polymer blends [2], to investigate the relaxation behavior and crystallization of novel bio-based aliphaticaromatic block copolymers [3], to study association mechanisms and limitations of these H-bonding polymers [4], to understand the occurrence of fast chain dynamics of polymers under extreme geometrical confinement [5], and to elucidate the role of solution filtering in the preparation of thin polymer films [6]. Dealing with smaller molecules, BDS has been combined with NMR to study the dynamics of asymmetric binary glass formers [7].…”