Influence of the Mesophase Structure on the .beta.-Relaxation in Comb-like Polymethacrylates

Schoenhals, Andreas; Wolff, Dietmar; Springer, Jürgen

doi:10.1021/ma00122a036

Cited by 45 publications

(28 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conductivity in PA-b-PS-b-PM, on the other hand, occurs at lower temperatures and with lower activation energies (~48 kJ mol −1 ), suggesting that σ dc may be activated by local motions. [74,80,81] Indeed, the activation energy of conductivity seems to be too low to be directly associated to the segmental motions of the α-relaxation, and, alternatively, it could have a similar molecular origin as the non-assigned βx-process, and being located at some specific sites near the polymer main chains. It is possible that the triblock structure may help disentangle local motions of the monomers, even though we note that it was difficult to discriminate by DSC between the glass transitions of each block (probably due to the small size of the domains discussed above).…”

Section: P# E a Kj Molmentioning

confidence: 99%

Liquid Crystalline Copolymers Containing Sulfonic and Light-Responsive Groups: From Molecular Design to Conductivity

et al. 2020

View full text Add to dashboard Cite

In the search for novel smart multifunctional liquid crystalline materials, we report the synthesis, thermal and structural characterisation, and the conductivity, of a set of new block and statistical copolymers, containing light-responsive mesogenic groups (MeOAzB), polar sulfonic acids (AMPS), and methyl(methacrylate) groups (MMA). By using a cascade of reversible addition-fragmentation chain polymerisations, RAFT, we have tailored different side-chain polymeric structures by controlling monomer composition (MeOAzB/AMPS/MMA) and configuration. We have yielded simultaneous liquid crystalline behaviour and appreciable conductivity in polymers with low concentrations of polar acid groups, by the formation of smectic phases in narrow aggregates. The light-responsiveness of the polymers, via reversible trans-to-cis photoisomerization of azobenzene groups, and the local activation of conductivity at relatively low temperatures, opens the possibility to prepare polymer electrolytes for energy conversion and storage, whose conductivity could be controlled and optimised by external stimuli, including light irradiation.

show abstract

Section: P# E a Kj Molmentioning

confidence: 99%

Liquid Crystalline Copolymers Containing Sulfonic and Light-Responsive Groups: From Molecular Design to Conductivity

et al. 2020

View full text Add to dashboard Cite

show abstract

“…It was found, that for comb‐like LC polymers, the molecular mobility of mesogenic groups (β‐process) weakly depends on their chemical structure, and the −logτ max = φ(1/ T ) dependence corresponds to the dashed Line 110–14 in Figure 2. The molecular mobility of the spacers (γ 1 ‐process) depends on their length, and the γ 1 ‐process is observed on the dielectric dependences, starting from n = 5–6.…”

Section: Resultsmentioning

confidence: 99%

“… Reciprocal temperature dependences of −logτ max for CP1–CP8 and for comb‐like LC polymers (dashed lines) in the range of the β‐ (110–14), γ 1 ‐ (210, 12, 15, 16), and γ 2 ‐processes (3 and 3′ 10–12, 17, 19…”

Section: Resultsmentioning

confidence: 99%

Local forms of molecular mobility in copolymethacrylates containing side‐chain nonlinear optical chromophores

Никонорова

Смирнов

Díaz‐Calleja

et al. 2008

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

Local forms of molecular mobility of comb‐like random copolymethacrylates, containing side‐chain nonlinear optical chromophores and amyl‐ or octafluoroamyl‐groups, are studied. In the glassy state, two relaxation processes are found, which are due to reorientation of terminal polar groups (γ2‐process) and rotation of chromophore groups about their long axes (β‐process). For octafluoroamyl‐containing copolymers, the γ2‐process is superposition of the two molecular motions due to reorientation of terminal chromophore groups and CF2H groups. The intensity and relaxation times in the range of the γ2‐process depend on the chemical structure and concentration of chromophores in a copolymer. For the β‐process, the molecular mobility weakly depends on the chromophore structure, being mainly determined by the relative lengths of the rigid chromophore and flexible side chains. On the global spectrum of depolarization current it was observed the γ1‐process due to reorientation of (CH2)n spacers between chromophore groups and copolymer backbone. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1488–1496, 2008

show abstract

“…7. The existence of such two relaxation modes in side-group LCP being well separated from a distinct dynamics of the polymer backbone has been reported for LC polycarbonates [31] and LC polyurethanes [14,32], and their link to a local order parameter was discussed in detail [33]. Since both 'mesogenic' relaxation modes (a* and d, also labeled as k 1 and k 2 in previous work [31]) could only be resolved for PCNO50, a possible trend in s d s a * as function of the chromophore concentration can not be discussed in this work.…”

Section: Effect Of Side Group Interactions On the Glass Transition Dymentioning

confidence: 91%

Optical and broadband dielectric investigations of photochromic polymethacrylates

Serwadczak

Wübbenhorst

Kucharski

2007

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

Influence of the Mesophase Structure on the .beta.-Relaxation in Comb-like Polymethacrylates

Cited by 45 publications

References 11 publications

Liquid Crystalline Copolymers Containing Sulfonic and Light-Responsive Groups: From Molecular Design to Conductivity

Liquid Crystalline Copolymers Containing Sulfonic and Light-Responsive Groups: From Molecular Design to Conductivity

Local forms of molecular mobility in copolymethacrylates containing side‐chain nonlinear optical chromophores

Optical and broadband dielectric investigations of photochromic polymethacrylates

Contact Info

Product

Resources

About