DNA-Inspired Strand-Exchange for Switchable PMMA-Based Supramolecular Morphologies

Abstract

Inspired by nanotechnologies based on DNA strand displacement, herein we demonstrate that synthetic helical strand exchange can be achieved through tuning of poly(methyl methacrylate) (PMMA) triple-helix stereocomplexes. To evaluate the utility and robustness of helical strand exchange, stereoregular PMMA/polyethylene glycol (PEG) block copolymers capable of undergoing crystallization driven self-assembly via stereocomplex formation were prepared. Micelles with spherical or wormlike morphologies were formed by varying the molecular weight composition of the assembling components. Significantly, PMMA strand exchange was demonstrated and utilized to reversibly switch the micelles between different morphologies. This concept of strand exchange with PMMA-based triple-helix stereocomplexes offers new opportunities to program dynamic behaviors of polymeric materials, leading to scalable synthesis of "smart" nanosystems.

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization

“…Recent advances to achieve two orthogonal stereoselective CAPs in one pot resulted in the in situ synthesis and fabrication of stereocomplexed poly­(MMA). Stereocomplexed poly­(MMA) exists as a triple-helix structure (a double helix of isotactic poly­(MMA) surrounded by a single helix of syndiotactic poly­(MMA)) formed through van der Waals interactions. − This supramolecular structure exhibits a significantly higher crystallinity and T m when compared to its individual stereoregular components that have been exploited for a variety of applications. ,,− Chen and co-workers recently used a mixture of C 2 - and C s -symmetric zirconocene bis­(ester enolate) catalysts to combine both synthesis and fabrication of stereocomplexed poly­(MMA) into a rapid single-step method . Polymer chain exchange between reactive centers was not evident, and real-time dynamic light scattering indicated that efficient stereocomplexation had occurred in situ as polymer chains were growing.…”

Synthesis and Self‐Assembly of Stimuli‐Responsive Amphiphilic Dendrimers

“…[15][16][17][18][19] Amphiphilic block copolymers are widely being used as key building blocks to create a variety of nanostructured materials such as micelles, vesicles, sheets, and tubes. [20][21][22][23] The morphological behavior would be controlled by altering the polymer properties such as hydrophilicity, hydrophobicity, flexibility, volume fraction, and composition. Significant efforts have been made to generate well-defined amphiphilic block copolymers that allow for precise control over the size and shape of their self-assembled structures.…”

Preparation of polyhedral oligomeric silsesquioxane‐containing block copolymer with well‐controlled stereoregularity

“…Although atactic polymethyl methacrylate (PMMA) does not form any specific structure, syndiotactic PMMA forms a helical structure, with 1 nm inner diameter and 2.3 nm outer diameter, in organic solvents. The syndiotactic PMMA encapsulates isotactic PMMA and functional molecules in their helical cavity . In this work, we report the preparation of a novel block copolymer consisting of syndiotactic PMMA and polymethacrylate‐functionalized POSS (PMAPOSS), designated as ( st ‐PMMA‐ b ‐PMAPOSS), and the encapsulation behavior of the st‐ PMMA segments in the block copolymer.…”