“Super microcapsules” (SMC). I. Preparation and characterization of star polymethylene oxide (PEO)polylactide (PLA) copolymers

Abstract

A new model of molecular scale microcapsule named “super microcapsule” (SMC) obtained from a star copolymer consisting of hydrophilic and hydrophobic blocks was presented. As a first stage, 3 and 4‐arm star polyethylene oxide‐polylactide copolymers (s‐PEO‐PLA) were synthesized by the use of triethanolamine and pentaerythritol and initiating agent, respectively. The block length of PLA and PEO for the copolymers can be controlled by feed and reaction conditions. The molecular weight distributions found to be in the range of 1.3–1.7. The DTA data indicated that the phase separation behavior of s‐PEOPLA copolymers is different from that of linear PEOPLA copolymers with comparable block length. As a evidence of SMC, the shell‐core structure of s‐PEOPLA copolymers in solid state was observed by TEM. The SMC dimensions were estimated to be about 400–1000 Å

Tailoring of block copolymers based on the stoichiometric control of the end-functionality of telechelic oligomers and the utilization of large-scale fractionation by phase fluctuation chromatography: A synthetic strategy for the preparation of end-functionalized poly(L-lactide)-block-poly(oxyethylene)

“…The relevant diblock copolymer, poly(L-lactide)-block-poly(oxyethylene) (PLLA-PEG), has been used for various purposes 3-7 since Zhu et al 8,9 first used it as a drug carrier. In particular, its amphiphilic nature and formation of micelles in aqueous media have attracted the attention of many researchers.…”

Molecular Dynamics of Podand Studied by Broadband Dielectric and Nuclear Magnetic Resonance Spectroscopies

“…[10] They have also been used as model compounds in the investigation of the key-and-lock matching mechanisms in biological systems. [11,12] For our investigation, we have chosen P-[O-(CH 2 CH 2 O) 10 -(CH 2 ) 15 -CH 3 ] 3 (P10.3H Podand) with a molecular weight of 2 074 g Á mol…”

Synthesis and properties of multiblock copolymers consisting of poly(L-lactic acid) and poly(oxypropylene-co-oxyethylene) prepared by direct polycondensation

“…16 -26 For example, Zhu et al first used the polymer micelles of a PEG-PLLA block copolymer in drug delivery. 27 A number of other researchers have also analyzed these polymer micelles incorporating drugs, 25,28 -31 as well as their prolonged circulation in the blood stream. 32 Polymer micro-spheres, films, and fibers of similar block copolymers were also reported to have high surface hydrophilicity due to the migration of the polyether segments to their surface region.…”