Evidence of dynamic heterogeneity as obtained from dielectric and Brillouin light-scattering studies of poly(n-hexylmethacrylate)

Embedding Nanofibers in a Polymer Matrix by Polymerization of Organogels Comprising Heterobifunctional Organogelators and Monomeric Solvents

“…In the DSC trace of polyHMA obtained at a heating rate of 10 °C min −1 , a glass transition was observed at −5 °C. The breadth of the glass transition was noticeably broad (25 °C), which is in agreement with a previous report . In contrast, the polymerized gel did not show any distinct transitions in the DSC trace.…”

Embedding Nanofibers in a Polymer Matrix by Polymerization of Organogels Comprising Heterobifunctional Organogelators and Monomeric Solvents

“…In the DSC trace of polyHMA obtained at a heating rate of 10 °C min −1 , a glass transition was observed at −5 °C. The breadth of the glass transition was noticeably broad (25 °C), which is in agreement with a previous report . In contrast, the polymerized gel did not show any distinct transitions in the DSC trace.…”

Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

“…If the glass temperature is defined as the point where the average relaxation time is about 100 s,44 these data would suggest that the glass temperature is somewhere near −5 °C. This is consistent with differential scanning calorimetry results of PHMA from Child (−5 °C),12 Hwang (−3 °C),3 and Meier (−5 °C)18 for heating at 20 °C/s. However, the transition measured by Meier was nearly 40 °C wide, and another measurement of the same sample by Beiner yielded a glass temperature of −19 °C for the same heating rate 45.…”

“…The measured Brillouin linewidths exhibit scatter in the data at all temperatures, but in general they start larger at higher temperatures, then decrease at lower temperatures. Meier reports Brillouin linewidths for PHMA over a temperature range from −50 to 300 °C 18. Data over the same temperature range as the present study exhibit the same linewidths within experimental error.…”

“…The LPR reported for many Brillouin scattering studies readily exceeds the intrinsic value. Meier reports an LPR of 8 at 50 °C,18 and Hwang reports an LPR of 2.3 at 25 °C for PHMA 3. This increase relative to the intrinsic value is a result of impurities in the sample that give rise to light scattering that does not come solely from longitudinal density fluctuations.…”

Confined Dynamics and Crystallization in Self-Assembled Alkyl Nanodomains

“…The α PE process is shifting to higher temperatures with increasing side-chain length while the trend for the α process is opposite. The decrease of the α relaxation temperature T α,10rad/s taken from the isochrones is comparable to the T g reduction seen in DSC scans for rran P3ATs and can be explained like in poly( n -alkyl methacrylates) and other side-chain polymers by internal plasticization effects ,, caused by highly mobile alkyl side chains in the environment of the main chains. The frequency temperature positions of the α PE processes in rreg P3ATs are comparable to those in rran P3ATs containing alkyl groups with identical length as well as those for many other nanophase-separated side-chain polymers (Figure b) .…”

Embedding Nanofibers in a Polymer Matrix by Polymerization of Organogels Comprising Heterobifunctional Organogelators and Monomeric Solvents

“…In the DSC trace of polyHMA obtained at a heating rate of 10 °C min −1 , a glass transition was observed at −5 °C. The breadth of the glass transition was noticeably broad (25 °C), which is in agreement with a previous report . In contrast, the polymerized gel did not show any distinct transitions in the DSC trace.…”

Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

“…If the glass temperature is defined as the point where the average relaxation time is about 100 s,44 these data would suggest that the glass temperature is somewhere near −5 °C. This is consistent with differential scanning calorimetry results of PHMA from Child (−5 °C),12 Hwang (−3 °C),3 and Meier (−5 °C)18 for heating at 20 °C/s. However, the transition measured by Meier was nearly 40 °C wide, and another measurement of the same sample by Beiner yielded a glass temperature of −19 °C for the same heating rate 45.…”

“…The measured Brillouin linewidths exhibit scatter in the data at all temperatures, but in general they start larger at higher temperatures, then decrease at lower temperatures. Meier reports Brillouin linewidths for PHMA over a temperature range from −50 to 300 °C 18. Data over the same temperature range as the present study exhibit the same linewidths within experimental error.…”

“…The LPR reported for many Brillouin scattering studies readily exceeds the intrinsic value. Meier reports an LPR of 8 at 50 °C,18 and Hwang reports an LPR of 2.3 at 25 °C for PHMA 3. This increase relative to the intrinsic value is a result of impurities in the sample that give rise to light scattering that does not come solely from longitudinal density fluctuations.…”

Confined Dynamics and Crystallization in Self-Assembled Alkyl Nanodomains

“…The α PE process is shifting to higher temperatures with increasing side-chain length while the trend for the α process is opposite. The decrease of the α relaxation temperature T α,10rad/s taken from the isochrones is comparable to the T g reduction seen in DSC scans for rran P3ATs and can be explained like in poly( n -alkyl methacrylates) and other side-chain polymers by internal plasticization effects ,, caused by highly mobile alkyl side chains in the environment of the main chains. The frequency temperature positions of the α PE processes in rreg P3ATs are comparable to those in rran P3ATs containing alkyl groups with identical length as well as those for many other nanophase-separated side-chain polymers (Figure b) .…”

Embedding Nanofibers in a Polymer Matrix by Polymerization of Organogels Comprising Heterobifunctional Organogelators and Monomeric Solvents

“…In the DSC trace of polyHMA obtained at a heating rate of 10 °C min −1 , a glass transition was observed at −5 °C. The breadth of the glass transition was noticeably broad (25 °C), which is in agreement with a previous report . In contrast, the polymerized gel did not show any distinct transitions in the DSC trace.…”

Evidence for the γ‐relaxation in the light scattering spectra of poly (n‐hexyl methacrylate) near the glass transition

“…If the glass temperature is defined as the point where the average relaxation time is about 100 s,44 these data would suggest that the glass temperature is somewhere near −5 °C. This is consistent with differential scanning calorimetry results of PHMA from Child (−5 °C),12 Hwang (−3 °C),3 and Meier (−5 °C)18 for heating at 20 °C/s. However, the transition measured by Meier was nearly 40 °C wide, and another measurement of the same sample by Beiner yielded a glass temperature of −19 °C for the same heating rate 45.…”

“…The measured Brillouin linewidths exhibit scatter in the data at all temperatures, but in general they start larger at higher temperatures, then decrease at lower temperatures. Meier reports Brillouin linewidths for PHMA over a temperature range from −50 to 300 °C 18. Data over the same temperature range as the present study exhibit the same linewidths within experimental error.…”

“…The LPR reported for many Brillouin scattering studies readily exceeds the intrinsic value. Meier reports an LPR of 8 at 50 °C,18 and Hwang reports an LPR of 2.3 at 25 °C for PHMA 3. This increase relative to the intrinsic value is a result of impurities in the sample that give rise to light scattering that does not come solely from longitudinal density fluctuations.…”

Confined Dynamics and Crystallization in Self-Assembled Alkyl Nanodomains

“…The α PE process is shifting to higher temperatures with increasing side-chain length while the trend for the α process is opposite. The decrease of the α relaxation temperature T α,10rad/s taken from the isochrones is comparable to the T g reduction seen in DSC scans for rran P3ATs and can be explained like in poly( n -alkyl methacrylates) and other side-chain polymers by internal plasticization effects ,, caused by highly mobile alkyl side chains in the environment of the main chains. The frequency temperature positions of the α PE processes in rreg P3ATs are comparable to those in rran P3ATs containing alkyl groups with identical length as well as those for many other nanophase-separated side-chain polymers (Figure b) .…”