Novel amphiphilic network polymers consisting of nonpolar, short primary polymer chains and polar, long crosslink units: Influence of characteristic dangling chains on swelling behavior of resulting amphiphilic gels

Abstract

Novel amphiphilic network polymers consisting of nonpolar, short primary polymer chains and polar, long crosslink units were prepared, and the swelling behavior of resulting amphiphilic gels is discussed by focusing on the influence of characteristic dangling chains; that is, benzyl methacrylate (BzMA) was copolymerized with tricosaethylene glycol dimethacrylate [CH2C(CH3)CO(OCH2CH2)23OCOC(CH3)CH2, PEGDMA‐23] in the presence of lauryl mercaptan as a chain‐transfer agent because BzMA forms nonpolar, short primary polymer chains and PEGDMA‐23 as a crosslinker contains a polar, long poly(oxyethylene) unit. The enhanced incorporation of dangling chains into the network polymer was brought by shortening the primary polymer chain length, and copolymerization with methoxytricosaethylene glycol methacrylate, a mono‐ene counterpart of PEGDMA‐23, enforced the incorporation of flexible dangling poly(oxyethylene) chains into the network polymer, although the former dangling chains as terminal parts of primary poly(BzMA) chains were rather rigid. Then, the influence of characteristic dangling chains on the swelling behavior of amphiphilic gels was examined in mixed solvents consisting of nonpolar t‐butylbenzene and polar methanol. The profiles of the solvent‐component dependencies of the swelling ratios were characteristic of amphiphilic gels. The introduction of dangling poly(oxyethylene) chains led not only to an increased swelling ratio but also to sharpened swelling behavior of amphiphilic gels. The swelling response of amphiphilic gels was checked by changing the external solvent polarity. The dangling chains with freely mobile end segments influenced the swelling response of gels. The amphiphilic gels with less entangled, collapsed crosslink units exhibited faster swelling response than the ones with more entangled, collapsed primary polymer chains. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2192–2201, 2004

Construction of Crosslink‐System‐Materials Utilizing Designed Network‐Polymer‐Precursor Modules

“…[22] This ideal NPP formation was developed to the preparation of novel amphiphilic polymers [11] and, moreover, amphiphilic CSMs. [37][38][39] As the latter case of controlling intramolecular crosslinking in the free-radical crosslinking monovinyl/divinyl copolymerization, we pursued the intramolecular crosslinking reaction to generate the net or loop structure as an origin of CSM, although the locally extensive occurrence of intramolecular crosslinking leads to microgelation. [3,[40][41][42][43][44] Eventually, we reached the preparation of novel loopstructures containing net polymers as the ultimate precursors of CSM consisting of microgel-like NPPs.…”

“…Thus, we could construct novel CSMs utilizing designed NPPs as modules, providing semi-interpenetrating polymer network (IPN) involving DAT networks and linear poly(BzMA), [46] and simultaneous-IPN between polymethacrylate and polyurethane networks, [47][48][49] novel amphiphilic CSMs [37][38][39]50,51] and patchwork-type CSMs, [52] and so on. Another example is concerned with the emulsion crosslinking (co)polymerization of multivinyl monomers, [53] especially focusing on the formation of reactive crosslinked polymer nanoparticles (CPNs) as models of microgels, with the intention of clarifying the correlation of the network structure with the reactivity of resulting CPNs which would be useful as functionalized polymeric materials.…”

Crosslinking diversity on network morphology, template binding, and template transport of molecularly imprinted polymers prepared via living radical polymerization

“…One reason for the lack of interest is the perceived unlikelihood that kinetic chain length is important in the kinetics of crosslinking systems that quickly form gels of infinite molecular weight. Though it may seem counterintuitive, recent research has shown that chain length does have a measurable effect on the polymerization kinetics of multi‐functional methacrylates . It has been demonstrated that chain length dependent termination is important in crosslinking systems.…”

“…It has been demonstrated that chain length dependent termination is important in crosslinking systems. Adding a chain transfer agent to the system or increasing the initiation rate (i.e., decreasing the kinetic chain length) leads to a more mobile reaction environment and more rapid termination . Additionally, the presence of a chain transfer agent alters the chemical identity of the radical fragment that begins a polymer chain.…”

“…In the presence of small amounts of chain transfer agents, it is unlikely that the chemical identity of this beginning fragment has any significant impact on the polymer properties or the network formation. Thus, the effect of chain transfer, even in these systems, is primarily on the kinetic chain length distribution . As the double bond conversion increases and reaction diffusion controlled termination begins to dominate the kinetics, the effect of kinetic chain length on the polymerization kinetics diminishes.…”