Breaking translational symmetry via polymer chain overcrowding in molecular bottlebrush crystallization

Abstract

One of the fundamental laws in crystallization is translational symmetry, which accounts for the profound shapes observed in natural mineral crystals and snowflakes. Herein, we report on the spontaneous formation of spherical hollow crystals with broken translational symmetry in crystalline molecular bottlebrush (mBB) polymers. The unique structure is named as mBB crystalsome (mBBC), highlighting its similarity to the classical molecular vesicles. Fluorescence resonance energy transfer (FRET) experiments show that the mBBC formation is driven by local chain overcrowding-induced asymmetric lamella bending, which is further confirmed by correlating crystalsome size with crystallization temperature and mBBʼs side chain grafting density. Our study unravels a new principle of spontaneous translational symmetry breaking, providing a general route towards designing versatile nanostructures.

Effect of Buffer Anions on Pearl-Necklace Morphology of Tertiary Amine-Containing Binary Heterografted Linear Molecular Bottlebrushes in Acidic Aqueous Buffers

“…Molecular bottlebrushes (MBBs), also called molecular brushes or brush polymers, are a special class of graft copolymers in which relatively short polymeric side chains are densely end-tethered to a long backbone polymer via a covalent bond. − These complex polymers have garnered considerable attention in recent years due to their many unique features, including composition and topology versatility, extremely high chain entanglement molecular weight, large and tunable persistence length, capability of shape changing in response to environmental variations, ,, and spontaneous symmetry breaking in crystallization at dilute conditions, which originate from their distinctive molecular structures. In particular, MBBs can exhibit a multitude of distinct conformations according to environmental conditions, and their large molecular sizes allow for facile visualization by atomic force microscopy (AFM) and transmission electron microscopy.…”

An efficient O-phthalaldehyde-amine coupling reaction for the synthesis of a bottlebrush polymer under physiological conditions

“…[1][2][3] Because of the steric hindrance of the side chains, the backbone is highly extended and exhibits a cylindrical conformation, endowing the bottlebrush polymers with unique structural and physical properties. [4][5][6][7] In the past decade, bottlebrush polymers have demonstrated many potential applications such as drug delivery, 8-10 catalysis, 11,12 antifouling materials, 13,14 lithographic patterning, 15,16 and so on.…”

Confined Crystal Melting in Edgeless Poly(l-lactic acid) Crystalsomes

“…An interesting question therefore arises: how does an edgeless lamellar crystal melt? To create an edgeless lamellar crystal, we consider the recently discovered spherical crystalsomes, which are single crystal-like hollow crystalline shells. − Due to its spherical shape, no exposed crystalline lateral surfaces exist in a closed crystalsome. Two types of approaches have been used to grow this unique structure.…”

“…Two types of approaches have been used to grow this unique structure. First, homopolymer and block copolymer crystalsomes were obtained using a miniemulsion crystallization method. − Second, molecular bottlebrushes with crystalline side chains were used to spontaneously form hollow crystalsomes . The present study concerns the structure and meting behavior of such crystalsomes.…”

“…11−13 Second, molecular bottlebrushes with crystalline side chains were used to spontaneously form hollow crystalsomes. 14 The present study concerns the structure and meting behavior of such crystalsomes. We shall focus on two aspects of the crystalsomes.…”