Shape thermoresponsive

Polyhedral niosomes were found to be thermoresponsive Fig. 7 (a). Above 35 °C, there was an increase in the release of CF from these niosomes even though the polyhedral shape was preserved until these vesicles were heated to 50 °C. Solulan C24-free polyhedral niosomes do not exhibit this thermoresponsive behavior [160] due to a decrease in the interaction of the polyoxyethylene compound solulan C24 with water at this temperature (due to decreased hydrogen bonding) as identified by viscometry [161]. This observed thermoresponsive behavior was used to design a reversible thermoresponsive controlled release system Fig. 7 (b). Thermoresponsive liposomal systems which rely on the changing membrane permeability, when the system transfers from the gel state (La) to the liquid crystal state (L 3) [162], are not reversible. This is not unex-... 

Li, S. C., and Tao, L. 2010. Melt rheological and thermoresponsive shape memory properties of HDPE/PA6/POE-g-MAHblends. Polymer—Plastics Technology and Engineering 49 218-222. 

Plamper FA, Ruppel M, Schmalz A, Borisov O, Ballauft M, Mueller AHE (2007) Tuning the thermoresponsive properties of weak polyelectrolytes aqueous solutions of star-shaped and linear poly(N, N-dimethylaminoethyl methacrylate). Macromolecules 40 8361-8366... 

Pretsch, T. (2010) Triple-shape properties of a thermoresponsive poly(ester urethane). Smart Materials and Structures, 19, paper 015006 (7 pages). 

It has been found that Mesua ferrea L. seed oil-based thermoplastic hyperbranched polyurethane (HBPU) of the monoglyceride of the oil, PCL (M = 3000 g moT ), 2,4/2,6-toluene diisocyanate and glycerol with 30% hard segment (NCO/OH = 0.96), exhibit thermoresponsive shape memory properties. The shape recovery (88,91 and 95%) and shape retention (70, 75 and 80%) are also found to be different at different temperatures (50, 60 and 70°C respectively). Bisphenol-A-based epoxy resin modified... 

Thermoresponsive shape recovery of epoxy resin-modified vegetable oil-based thermosetting hyperbranched polyurethane. 

PL3 Plamper, F.A., Ruppel, M., Schmalz, A., Borisov, O., Ballauff, M., and Muller, A.H.E., Timing the thermoresponsive properties of weak polyelectrolytes Aqueous solutions of star-shaped and linear poly(A,A-dimethylaminoethyl methacrylate), Macromolecules, 40, 8361, 2007. 

Garle A et al (2012) Thermoresponsive semicrystalline poly(c-caprolactone) networks exploiting cross-linking with cinnamoyl moieties to design polymers with tunable shape memory. ACS Appl Mater Interfaces 4(2) 645-657... 

Thermoresponsive self-folding films can be designed using continuous thermal expansion, melting, shape-memory transition or polymers which demonstrate LCST (Low Critical Solution Temperature) behavior in solutions. Kalaitzidou et al. used continuous volume expansion with temperature and demonstrated thermoresponsive rolling-unrolling of polydimethylsiloxane-gold bilayers tubes at 60-70 °C [24a, 24b] which is due to different temperature expansion coefficients. 

Lendlein et al. demonstrated the possibilities to design thermoresponsive macroscopic self-folding objects using shape-memory polymers based on different poly(e-caprolactone) [12]. At low temperature, the materials are in their temporary shape. The films recover their permanent shape and irreversibly fold by heating, which could be accompanied by a change of transparency. 

Adjustable breathability is an area where responsive barriers have already found commercial applications. For example, a thermoresponsive breathable membrane using shape memory polyurethane has been developed by Mitsubishi Heavy Industries (SMP Technologies Inc., 2010). It can be laminated onto various types of textiles to provide waterproof, windproof yet breathable clothing. Another strategy based on a temperature-activated breathable monolithic film sandwiched between two layers of spunbond microfibrous polypropylene has been used by Ahlstrom Corp. to develop medical gowns that combine protection against virases with comfort and breathabUity (Rodie, 2005). 

Synthesis of various functionalized 2008 [30] iV-isopropylacrylamide- and vinylether-based polymers grafting onto various substrates detailed review of thermoresponsive polymers, block and graft copolymers synthesis of PiPAAm of various shapes ionic and neutral block copolymers self-assembly stimuli-responsive polymers new initiating systems and synthetic methodologies... 

The polymer architecture affects the demixing behaviour of thermoresponsive polymers [562], On the basis of theoretical studies it is expected that, as a rule, branched macromolecules are more soluble than their linear analogues [563-565]. This prediction was confirmed experimentally in the case of a solution of star-like polystyrene in cyclohexane (an UCST-type phase separation) for which an increase in the degree of branching resulted in a decrease in the temperature of demixing [566, 567], On the basis of a review of water-soluble polymers of various shapes by Aoshima and Kanaoka [30], it appears that water-soluble polymers do not offer a uniform tendency in their LCST-type phase behaviour. 

The third group includes thermoresponsive polymers. The strategy to apply magnetic induction to these materials allows the development of both implantable and shape-memory devices (Thevenot et al. 2013). 

Promising developments are further expected from stimuli sensitive, mainly pH and thermoresponsive systems that change their volume and shape according to external physicochemical factors. Typical examples of such block copolymer micelles mainly based on PNIPAM were described by different authors [176,177,305,306],... 

Abstract This chapter describes polymers that undergo a temperature-induced phase transition in aqueous solution providing an important basis for smart materials. Different types of temperature-responsive polymers, including shape-memory materials, hquid crystalline materials and responsive polymer solutions are briefly introduced. Subsequently this chapter will focus on thermoresponsive polymer solutions. At first, the basic principles of the upper and lower critical temperature polymer phase transitions will be discussed, followed by an overview and discussion of important aspects of various key types of such temperature-responsive polymers. Finally, selected potential apphcations of thermoresponsive polymer solutions will be described. 

Schematic representation of the thermoresponsive behavior of a shape-memory polymer. 7 represents the 7 of the hard phase and 71 represents the 71 of the switching phase. 

Chung S.E., Park C.H., Yu W.R. and KangT.J. (2011),Thermoresponsive shape memory characteristics of polyurethane electrospun web. Journal of Applied Polymer Science, 120(1) pp. 492-500. 

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