Design of Oligo(ethylene glycol)-Based Thermoresponsive Polymers: an Optimization Study

Abstract

Co-polymers of 2-(2-methoxyethoxy)ethyl methacrylate (MEO 2 MA) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA 300 , M n = 300 g/mol) of various composition were synthesized at 60 • C in ethanol solution either by conventional radical polymerization (RP) or atom transfer radical polymerization (ATRP). Both techniques led to co-polymers P(MEO 2 MA-co-OEGMA 300 ) in high yields. However, ATRP provided better defined co-polymers with controlled molecular weight, composition and molecular weight distribution. Nevertheless, all the samples exhibited a lower critical solution temperature (LCST) in aqueous medium (i.e., pure deionized water or physiological buffer). Sharp and reversible phase transitions were observed in all cases by turbidimetry and dynamic light scattering. This thermoresponsive behavior was demonstrated to be directly linked to the MEO 2 MA/OEGMA 300 composition of the formed co-polymers. Thus, the LCST of the co-polymers could be precisely adjusted in the temperature range 28-65 • C. © Koninklijke Brill NV, Leiden, 2009

Thermo‐Switchable Materials Prepared Using the OEGMA‐Platform

“…[20][21][22] For instance, our research group described the synthesis of thermoresponsive copoly mers by atom transfer radical copolymerization of 2-(2-methoxyethoxy)ethyl methacrylate (MEO 2 MA, Figure 1 ) with oligo(ethylene glycol) methyl ether methacrylates (e.g., OEGMA 475 , M n = 475 g · mol − 1 or OEGMA 300 , M n = 300 g · mol − 1 , Figure 1 ). [23][24][25][26] These copolymers combine the advantages of PEG (i.e., biocompatibility) and thermoresponsive polymers (i.e., LCST behavior in water) in a single macromolecular structure. Moreover, they have inherent advantages as compared to traditional PNIPAM such as: (i) an excellent bio-repellency below LCST (i.e., anti-fouling behavior), (ii) reversible phase transitions (i.e., no marked hysteresis), and (iii) bio-inert properties (i.e., no specifi c interactions with biological materials).…”

Thermoresponsive Behavior of Mixtures of Epoxy Functionalized Oligo(ethylene glycol) Methacrylate Copolymers

“…However, thermoresponsive (meth)acrylic polymers containing short oligo(ethylene glycol), OEG, side chains, P(OEG x MA), were recently proposed as a very attractive alternative. [16][17][18][19][20][21][22][23][24] They also show a sharp and reversible LCST, which values depend on the length of the OEG side chain but moreover, they present some other advantages. On the one hand, the LCST can be modulated by copolymerisation of several of these macromonomers.…”

Tuning thermoresponsive behavior of diblock copolymers and their gold core hybrids

“…Recently, polymerizable (meth)acrylates, such as oligo(ethylene glycol) methyl ether acrylate (OEGA, M n = 480 g/mol), oligo(ethylene glycol) methyl ether methacrylate (OEGMA, M n = 475 g/mol), and di(ethylene glycol) methyl ether methacrylate (DEGMA), have been studied as alternatives [14][15][16][17][18][19][20][21][22][23][24][25] to PNIPAM. We are interested in these monomers for use as injectable nanoparticles for drug delivery applications, as these materials are biocompatible and the pendant oligo-ethylene glycol units should alleviate the need to PEGylate the nanoparticles to prevent non-specific protein absorption [26].…”

“…Also, the LCSTs of copolymers prepared using these monomers are tunable. For example, Lutz and co-workers carried out several studies of PEG-based copolymers [14][15][16][17][18]. They prepared statistical copolymers of P(DEGMA-co-OEGMA 475 ) using atom transfer radical polymerization (ATRP) and showed a linear correlation between LCST and the mole fraction of the more hydrophilic monomer in their statistical copolymers.…”

“…Furthermore, RAFT avoids the need to use a copper salt. We also chose to use OEGA and DEGMA rather than two acrylates or two methacrylates, as was done in other studies [14][15][16][17][18][19][20][21][22][23][24][25] because the acrylate backbone of OEGA is slightly more hydrophilic than OEGMA, with its methyl group, while DEGMA, possessing the added methyl group, is slightly more hydrophobic than DEGA. Therefore, the difference in hydrophilicity of the two blocks is slightly accentuated.…”