Effects of Glycine‐Based Ionic Liquid on Spherulite Morphology of Poly(l‐Lactide)

Abstract

Crystalline morphology, lamellar assembly, spherulitic growth rate, and physical properties of poly(l‐lactide acid) (PLLA) modified by a room‐temperature ionic liquid (IL), N‐alkyl‐substituted‐glycine ester [N,N‐dimethyl‐N‐propyl glycine ethyl ester (DMPGlyET)+] bis(fluoromethanesufonyl)imide [TFSI−], are investigated by using polarized optical microscopy, optical microscopy, differential scanning calorimetric, and atomic‐force microscopy. Thermal analyses and in situ microscopy characterization reveal the PLLA/IL mixture with upper‐critical‐solution‐temperature behavior. Crystalline morphology of PLLA is significantly changed by the addition of IL to display massive diversification of spherulites morphology which has never been reported before in neat PLLA or PLLA blends with polymers. The morphological change and diversifications in PLLA/IL mixture are associated with strong interactions between PLLA and IL, which impede the melt crystallization of PLLA and tend to form PLLA nuclei of various geometry shapes. In addition, neat PLLA is generally brittle with extensive crack formation during postcrystallization cooling process; however, with the addition of IL, cracks are reduced or diminished entirely, potentially to enhance the performance and properties of PLLA.

Explosive Fibonacci-sequence growth into unusual sector-face morphology in poly(l-lactic acid) crystallized with polymeric diluents

“…Radial-oriented main lamellae with branching of platelet lamellae into perpendicularly grating structures are often observed in crystallization of PLLA in PLLA-diluent blends; however, the nature of the diluent, with different interacting intimacy with PLLA chains, may govern the growth and assembly of the lamellae in final spherulites. For PLLA crystallized with more strongly interacting diluents, such as ionic liquids or poly(p-vinyl phenol) (PVPh), the spherulitic PLLA morphologies are also different from www.nature.com/scientificreports/ those in the PLLA/PMMA blends, but no sector-face PLLA spherulites were ever found in either PLLA/ionic liquids or PLLA/PVPh blends 14,20,21 . These cases demonstrate the effects of diluents and film thickness, as well as T c of course, on the lamellar assembly patterns in PLLA spherulites.…”

Unique Periodic Rings Composed of Fractal-Growth Dendritic Branching in Poly(p-dioxanone)

“…Many semicrystalline polymers, when blended with strongly interacting hydroxyl-containing PVPh, may exhibit dendritic spherulites packed with feather-like lamellae [ 26 , 27 , 28 ]. More peculiarly, ring bands can be superimposed on the fibrous dendrites to collectively form banded dendrites in final aggregated assemblies.…”

Facile Synthesis of Ag/Ag3PO4 Composites with Highly Efficient and Stable Photocatalytic Performance under Visible Light

“…To date, many researchers have dedicated their efforts to its controllable synthesis and focused on the structure and morphology of the catalysts, such as nanotubes, spheres, cube, rhombic dodecahedra, tetrapods, myriapods, truncated tetragonal bipyramid hollow microboxes, and so on. However, most of these different morphologies of Ag 3 PO 4 have been prepared by adding surfactants such as hexamethylenetetramine (HMT), poly(vinyl pyrrolidone) (PVP), glycine, ethanol, DMF, and sodium oxalate . Besides, Ag 3 PO 4 is not stable during the photocatalytic process because of photocorrosion, meaning that in the absence of an electron acceptor, the photo‐generated electron decomposes Ag 3 PO 4 on light illumination.…”