Hierarchically organized micellization of thermoresponsive rod‐coil copolymers based on poly[oligo(ethylene glycol) methacrylate] and poly(ε‐caprolactone)

Abstract

A series of amphiphilic triblock copolymers, poly [oligo(ethylene glycol) methacrylate] x -block-poly(e-caprolactone)-block-poly[oligo(ethylene glycol) methacrylate] x , POEGMA Co (x), were synthesized. Formation of hydrophobic domains as cores of the micelles was studied by fluorescence spectroscopy. The critical micelle concentrations in aqueous solution were found to be in the range of circa 10 À6 M. A novel methodology by modulated temperature differential scanning calorimetry was developed to determine critical micelle temperature. A significant concentration dependence of cmt was found. Dynamic light scattering measurements showed a bidispersed size distribution.The micelles showed reversible dispersion/aggregation in response to temperature cycles with lower critical solution temperature between 75 and 85 C. The interplay of the two hydrophobic and one thermoresponsive macromolecular chains offers the chance to more complex morphologies. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4909][4910][4911][4912][4913][4914][4915][4916][4917][4918][4919][4920][4921] 2010

Synthesis, self-assembly, and thermosensitivity of amphiphilic POEGMA-PDMS-POEGMA triblock copolymers

“…The micelle formation of copolymer samples was determined by a fluorescent probe technique using pyrene . Pyrene is a hydrophobic fluorescent molecule; its fluorescence behavior in the aqueous medium differs from that in the micelle interior.…”

Thermo-responsive drug release from self-assembled micelles of brush-like PLA/PEG analogues block copolymers

“…As summarized in Table 2, the CMC value of triblock copolymers increases from 0.0113 to 0.0130 mg mL À1 as the content of OEGMA increased from 21 to 58% due to the higher hydrophilicity of OEGMA units as compared to MEO 2 MA ones. The CMC is 10 times lower than that of POEGMA-PLLA-POEGMA copolymers (0.08-0.12 mg mL À1 ) reported by Bakkour et al and twice lower than that of POEGMA-b-PCL-b-POEGMA micelles (0.0254-0.0372 mg mL À1 ) reported by Luzon et al (Bakkour et al, 2013 andLuzón et al, 2010). In this work, the lower CMC of copolymers could be assigned to the presence of MEO 2 MA moieties which are less hydrophilic than OEGMA ones (Lutz et al, 2008).…”

“…In fact, the properties of PLA/PEG analogues copolymer and resulting micelles are affected by the hydrophobic/ hydrophilic balance, the ratio of comonomers, the graft density, the graft length etc. (Bakkour et al, 2013;Fenyves et al, 2014;Luzón et al, 2010;Saeed et al, 2009 Fig. 2 presents the SEC curves of the copolymers.…”

“…And polymethylacrylate (PMA) blocks are located at the interface. Indeed, PMA presents stronger affinity to water than PLLA due to the surface active ester groups attached to hydrophilic EG units (Luzón et al, 2010). Consequently, copolymer micelles exhibit less compact structure as compared to P(NIPAAm-co-DMAAm)-b-PLLA-b-P(NIPAAm-co-DMAAm).…”

“…These PEG analogues exhibited a LCST between 26 and 90 C which can be precisely adjusted by varying the co-monomers ratio, which could be attractive for targeted drug delivery because of their thermo-responsive properties and outstanding biocompatibility similar to linear PEG. Later on, the synthesis and micellization of PLA/PEG analogues copolymers have been studied (Bakkour et al, 2013;Fenyves et al, 2014;Luzón et al, 2010;Saeed et al, 2009). Nevertheless, the LCST of these copolymers was above 75 C, which greatly diminishes their potential as drug carrier.…”