Self-Organization Behavior of Methacrylate-Based Amphiphilic Di- and Triblock Copolymers

Abstract

Amphiphilic di- and triblock copolymers having different hydrophilic-to-hydrophobic block length ratio were synthesized using ATRP. The self-assembly behavior of these AB and ABA block copolymers consisting of poly(n-butyl methacrylate) (B) and poly(2,2-(dimethylaminoethyl methacrylate) (A) was investigated using a combination of dynamic light scattering, negative-stain transmission electron microscopy, cryoelectron microscopy, and atomic force microscopy. Two populations of self-organized structures in aqueous solution, micelles and compound micelles, were detected for diblock copolymers. Triblock copolymers assembled into vesicular structures of uniform sizes. Furthermore it was found that these vesicles tended to compensate the high curvature by additional organization of the polymer chains outside of the membrane. The chain hydrophilicity of the polymers appeared to have a critical impact on the self-assembly response toward temperature change. The self-reorganization of the polymers at different temperatures is discussed.

Carbohydrate-Conjugated Amino Acid-Based Fluorescent Block Copolymers: Their Self-Assembly, pH Responsiveness, and/or Lectin Recognition

“…The construction of nanoparticle reinforce us to rely the presence of both hydrophobic segments (methacrylate backbone and alkyl groups in valine repeating unit) as well as hydrophilic segments (-NH 3 + pendants in valine and glucose units with -OH groups) in the block copolymer 10, thus manifested the projection of dual amino and sugar residues to the outer surface of nanoparticle. The experimental size of the achieved micelles from these block copolymers were in reasonable agreement with the theoretical diameters of micellar size estimated by contour length calculation of copolymers (see in the SupportingInformation) 36,37. Moreover, the appearance of large multimolecular composites with thermodynamically stable structures were also observed by FE-SEM in all the above three cases (Figure S5, Supporting Information), formed by the aggregation of those preformed small micelles 33,[37][38][39].…”

“…The experimental size of the achieved micelles from these block copolymers were in reasonable agreement with the theoretical diameters of micellar size estimated by contour length calculation of copolymers (see in the SupportingInformation) 36,37. Moreover, the appearance of large multimolecular composites with thermodynamically stable structures were also observed by FE-SEM in all the above three cases (Figure S5, Supporting Information), formed by the aggregation of those preformed small micelles 33,[37][38][39]. The emergence of such micellar aggregation can possibly be attributed to the hydrogen bonding based secondary interactions involved due to the existence of amide or amino groups from amino acid moieties and hydroxyl groups of carbohydrate residues in the block copolymers, as well as the variation in hydrophilic/hydrophobic weight ratios in those amphiphilic copolymers 12,40.…”

Stimuli‐Responsive Polymersomes as Nanocarriers for Drug and Gene Delivery

“…Some of these systems are currently on the market (Lumirem® from Guebert S. A. or Abraxane® from American Bioscience Inc. etc); many clinical evaluations of others are in progress. Additionally, recent achievements in polymerization techniques allow preparation of stimuli‐responsive polymers with controlled molecular architecture, weight and polydispersity 12–14. These are steps towards an ideal DDS which would have a high drug loading capacity, adequate stability in the bloodstream, long circulation properties, and selective accumulation at the site of action together with a suitable drug release profile and good biocompatibility.…”

Polymersome/Silica Capsules by ‘Click’‐Chemistry

“…Polymersomes1–3 are vesicle‐like polymeric capsules made from di‐ and triblock copolymers4–8 in organic and aqueous solution, and are often used for delivery purposes3, 5, 6 and encapsulation 9, 10. Similar to their lipid counterparts,11 their membrane is made by the spontaneous self assembly of oligomeric building blocks from solution, however, with variable thickness and stronger membrane moduli 12, 13.…”