Crystalline Polymers in Nanoscale 1D Spatial Confinement

Abstract

A series of semicrystalline block copolymers, poly(4-vinylpyridine)-block-poly(ε-caprolactone) (P4VP−PCL), with lamellar microstructure have been synthesized. Owing to the vitrified P4VP microdomains and strongly segregated microphase separation, the crystallization of the PCL blocks in P4VP−PCL was carried out within the nanoscale confinement. Simply by varying the molecular weight of the block copolymer, namely the confined size, polymeric crystallization can be tailored in the one-dimensional confinement. A distinct nucleation mechanism, altering from heterogeneous to homogeneous nucleation, was obtained once the confined size became smaller than a critical dimension, equivalent to the regular thickness of heterogeneously nucleated crystalline lamellae. Consequently, discrete crystalline granules were generated through homogeneous nucleation, namely a single nucleus within one granule. Also, crystal growth was altered from specific to random orientation with respect to the interface between the crystalline and amorphous domains in the copolymers. This system thus serves as a model to analyze the impact of confined size in 1D spatial confinement on the crystallization of polymers.

Entrapment of functionalized silica microspheres with photo-initiated acrylate-based polymers

“…Surfaces exert influence on the nearby polymer to a certain degree, and when a system is such that polymer is forced to be largely near surfaces, this influence can no longer be ignored [36]. It is known that for a number of polymer properties, including those related to crystallization [37], chain association [38], glass transition temperature (T g ) [39] and physical aging [40,41], the confinement of the system to small spaces can cause some interesting effects, and sometimes can completely alter the chemistry. In our case, the spaces between the 3 µm spheres represent interfaces of surfaces less than a micron apart, within the range where the effects of confinement can be expressed.…”

Impact of Nanoscale Confinement on Crystal Orientation of Poly(ethylene oxide)

“…[3][4][5][6][7] At the other extreme, ''in-plane'' lamellae with chain orientation perpendicular to the layers are observed. [8][9][10][11] Although speculation is possible, [12,13] the origin for the specific orientation has not been clearly elucidated. Understanding of the nucleation and growth processes that control crystal orientation is needed.…”

Composition Dependence of Crystallization Behavior Observed in Crystalline-Crystalline Diblock Copolymers

“…Therefore the crystallized morphology formed by high-T m blocks is a kind of spatial confinement for the subsequent crystallization of low-T m blocks, which will be qualitatively different from the confinement imposed by amorphous or glassy microdomains observed in crystallineamorphous diblock copolymers. [9][10][11] There are some studies so far on the morphology formation of double crystalline block copolymers with different T m values, [12][13][14][15][16][17][18][19][20][21][22][23][24] where they are mainly focused on the characteristic morphology finally formed in the system.…”