Direct Observation of Crystal−Amorphous Interphase in Lamellar Semicrystalline Poly(ethylene terephthalate)

Ivanov, Dimitri A.; Pop, Tatiana; Yoon, D. Y.; Jonas, Alain M.

doi:10.1021/ma011784j

Cited by 59 publications

(45 citation statements)

References 32 publications

(49 reference statements)

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“…In general, small angle X-ray scattering (SAXS) is a very suitable tool to study the development of these arrays of lamella [3]. The, either homogeneous or heterogeneous, nature of the distribution of lamellar stacks in the system has been a subject of extended debate in the last years [1,[4][5][6][7][8][9]. Traditionally, the observation of the crystalline phase evolution has been performed by diffraction techniques [10] and by microscopy techniques [11].…”

Section: Introductionmentioning

confidence: 99%

Order and segmental mobility during polymer crystallization: Poly(butylene isophthalate)

Sanz

Nogales

Ezquerra

et al. 2006

Polymer

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The influence of the development of crystalline structure on the segmental dynamics of the amorphous phase in poly(butylene isophthalate) (PBI) has been studied by a combination of relaxation and scattering techniques. By means of dielectric spectroscopy (DS) the dynamics of both amorphous and semicrystalline PBI samples has been observed in a wide frequency and temperature range. The evolution of the crystalline phase with time has been studied in a range of temperatures, starting from initially glassy PBI by simultaneous small and wide angle X-ray scattering (SWAXS). By using a state-of-the-art setup designed specifically for the in situ study of both DS and SWAXS simultaneously (SWD), the crystallization of initially amorphous PBI has been followed in real time from both the structural and dynamics points of view. The obtained results support a model based on two different regimes on crystallization and a heterogeneous distribution of lamellar stacks. During the first regime the primary stacks cause the apparition of a rigid amorphous phase (RAP), i.e. a phase of amorphous chains lacking segmental motion. During the second regime, however, no more RAP is observed, indicating that the new lamellae that appear during this stage are nearly individual and not forming lamella stacks. q

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Section: Introductionmentioning

confidence: 99%

Order and segmental mobility during polymer crystallization: Poly(butylene isophthalate)

Sanz

Nogales

Ezquerra

et al. 2006

Polymer

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“…The similarity in inelastic neutron scattering of the semicrystalline and amorphous phases indicates a highly disordered bulk crystal. This disorder is also present at the surface as examined by AFM, transmission electron microscopy, dielectric spectroscopy, and neutron scattering studies, which revealed amorphous-crystal interphases in lamellar stacks of PET (49)(50)(51).…”

Section: Discussionmentioning

confidence: 93%

Comparative surface dynamics of amorphous and semicrystalline polymer films

Becker

Brown

Killelea

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The surface dynamics of amorphous and semicrystalline polymer films have been measured using helium atom scattering. Timeof-flight data were collected to resolve the elastic and inelastic scattering components in the diffuse scattering of neutral helium atoms from the surface of a thin poly(ethylene terephthalate) film. Debye-Waller attenuation was observed for both the amorphous and semicrystalline phases of the polymer by recording the decay of elastically scattered helium atoms with increasing surface temperature. Thermal attenuation measurements in the specular scattering geometry yielded perpendicular mean-square displacements of 2.7 • 10 −4 Å 2 K −1 and 3.1 • 10 −4 Å 2 K −1 for the amorphous and semicrystalline surfaces, respectively. The semicrystalline surface was consistently ∼15% softer than the amorphous across a variety of perpendicular momentum transfers. The Debye-Waller factors were also measured at off-specular angles to characterize the parallel mean-square displacements, which were found to increase by an order of magnitude over the perpendicular mean-square displacements for both surfaces. In contrast to the perpendicular motion, the semicrystalline state was ∼25% stiffer than the amorphous phase in the surface plane. These results were uniquely accessed through low-energy neutral helium atom scattering due to the highly surface-sensitive and nonperturbative nature of these interactions. The goal of tailoring the chemical and physical properties of complex advanced materials requires an improved understanding of interfacial dynamics, information that is obtainable through atomic beam scattering methods.atomic beam scattering | gas-surface Interactions | dynamics of polymer interfaces | polymer surfaces A tom scattering has been used to quantify key surface dynamical properties of systems of increasing complexity. Early work focused on understanding the gas-surface interaction and surface structure and dynamics of ionic (1, 2), metallic (3), and semiconductor (4) surfaces. Building on the pioneering work performed on single-crystal surfaces, further molecular beam investigations examined systems of greater structural complexity including surface defects (5), stepped surfaces (6), and adsorbates on surfaces (7,8). The success of these forays into disordered and complex systems, bolstered by advances in scattering theory (9-11), led to the study of soft organic interfaces such as liquids (12, 13), self-assembled monolayers (SAMs) (14-17), and, most recently, thin polymer films (18)(19)(20). In this work, we present the successful extension of helium atom scattering, a uniquely surface-sensitive probe, to determining the changes in local surface vibrational dynamics due to crystallization of a thin polymer film.Interfaces of thin molecular films have recently received significant attention to uncover the surface structure and properties as well as the interface's ultimate effect on bulk material properties. In particular, polymer films present a complex, macromolecular interface of importance in f...

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“…In particular, the existence of interfacial regions with properties lying between those of crystalline and undisturbed amorphous regions has been revealed by quantitative comparisons of the degree of crystallinity, determined by distinct methods [88,89]. Although the existence of the order-disorder transition region at the crystal-amorphous boundaries is well demonstrated, until the recent work of Ivanov and co-workers [90] there was no direct experimental demonstration of the crystal-amorphous interface. This evidence was obtained by transmission electron microscopy (TEM) observation of the compositional variation of stained PET segments in the boundary of an isolated lamellar stack in a binary blend of semicrystalline PET with amorphous poly(ether imide) (PEI) [90].…”

Section: Influence Of Crystallinity On the Glass Transition Dynamicsmentioning

confidence: 99%

“…Although the existence of the order-disorder transition region at the crystal-amorphous boundaries is well demonstrated, until the recent work of Ivanov and co-workers [90] there was no direct experimental demonstration of the crystal-amorphous interface. This evidence was obtained by transmission electron microscopy (TEM) observation of the compositional variation of stained PET segments in the boundary of an isolated lamellar stack in a binary blend of semicrystalline PET with amorphous poly(ether imide) (PEI) [90].…”

Section: Influence Of Crystallinity On the Glass Transition Dynamicsmentioning

confidence: 99%

Molecular dynamics in polymeric systems

2004

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It is well known that the properties of polymeric materials depend strongly upon their chemical structure. Other more specific factors that may be related to the chemical structure also determine the macroscopic behaviour of such materials, namely the relative position of the different segments of the polymeric chain, the molecular architecture (molecular weight distribution, branching, copolymer organisation, cross-linking extent, etc.), the crystalline environment and the pressure/temperature conditions. All these factors have a common impact in the material: they are strongly correlated to the mobility on the molecular level. That is why a huge amount of work has been devoted to the study of translational/rotational mobility that occurs within the polymeric chains. This review is intended to provide a brief survey on such kinds of mobilities, how they can be studied and what are their main characteristics. Examples on systems studied in our groups will be provided, obtained by dielectric and mechanical spectroscopies and differential scanning calorimetry. It will be mainly focused on molecular motions that occur in the solid phase (i.e., to temperatures up to the rubbery plateau). The dynamics in blends or copolymers will be avoided here, as they would deserve a special discussion in their own context. Special attention will be paid to the glass transition and the mobility that occurs below and above it. The dynamics that are observed in peculiar systems, such as semi-crystalline or liquid crystalline polymers, will be addressed.

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Direct Observation of Crystal−Amorphous Interphase in Lamellar Semicrystalline Poly(ethylene terephthalate)

Cited by 59 publications

References 32 publications

Order and segmental mobility during polymer crystallization: Poly(butylene isophthalate)

Order and segmental mobility during polymer crystallization: Poly(butylene isophthalate)

Comparative surface dynamics of amorphous and semicrystalline polymer films

Molecular dynamics in polymeric systems

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