PH- and thermo-responsive polymers

SIB Siband, E., Tran, Y., and Hourdet, D., pH- and thermo-responsive polymer assemblies in aqueous solution, Progr. Colloid Polym. Sci., 137, 19, 2010. 

SHT Shtanko, N.I., Lequieu, W., Goethals, E.J., and DuPrez, F.E., pH- and thermo-responsive properties of poly(A-viiwlcaprolactam-co-acrylic acid) copolymers, Polym. Int. 52, 1605, 2003. 

Lee Y M, Kim S H and Cho C S, Synthesis and swelling characteristics of pH and thermo-responsive interpenetrating polymer network hydrogel composed of poly(vinyl alcohol) and polyfacryUc acid) , J. Appl. Polym. Sci., 1996, 62, 301. 

Shin, H.S., Kim, S.Y., Lee, Y.M., 1997. Indomethacin release behaviors from pH and thermo-responsive poly(vinyl alcohol) and poly(acrylic acid) IPN hydrogels for site-specific drug delivery. J. Appl. Polym. Sci. 65 (4), 685-693. 

Thermo-responsive polymers have been used to release encapsulated drugs in response to temperature changes. These polymers typically undergo a rapid and reversible hydration-dehydration at lower critical solution temperature (LCST, from soluble to insoluble) or upper critical solution temperature (UCST, from insoluble to soluble) upon heating. [71] For example, a thermo-responsive polymer, poly (2-isopropyl- 2-oxazoline) (PiPrOx), was conjugated to pH-responsive poly(benzyl ether)dendrons, which exhibited sharp thermal transitions as well as pH-dependent behaviors (Fig. 4a).[105]... 

It would be of interest to add some functionalities such as properties in response to changes in pH, temperature, electrical potential and so on as well as hydrophilic properties to PTFE surfaces by the combined technique just described. Poly(AT-isopropylaoylamide) (PNIPA ) is a well-known thermo-responsive polymer whose hydrogel undergoes a volume change around 31 C in an aqueous solution. And further, poly 2-(dimethylamino)ethyl methacrylate (PDMA) in a pH 10 buffer solution exhibits a drastic decrease in the transmittance around 28 °C, which is considered to come from a phase transition of PDMA chains (ii). Therefore, we have tried to prepare JV -isopropylacrylamide (NIPAAm) or 2-(dimethylamino)ethyl... 

In a previous study, our group synthesized a new temperature and pH-sensitive poly(2-(dimethylamino) ethylmethacrylate-fe-vinylcaprolactam-fc-(2-(dimethylamino) ethyl methacrylate)), PDMAEMA- i-PVCL-fc-PDMAEMA, triblock copolymer by RAFT polymerization. PDMAEMA is dual sensitive (pH and temperature) and its LCST was around 50 °C, while PVCL is a thermo-responsive polymer and its LCST was around 32 °C. By modifying the structure and adjusting the composition of these polymers it is possible reduce the LSCT and pK values in order to ensure compatibility with physiological temperature and pH (see Table 9.1, Triblock 1). The results showed that these polymers can self-assemble into micelles in different environments [60]. 

Twaites BR, CdlH A, Cunliffe D et al (2004) Thermo and pH responsive polymers as gene delivery vectors effect of polymer architecture on DNA complexation in vitro. J Control Release 97 551-566... 

Ruiz, J.C., Burillo, G., and Bucio, E. 2007. Interpenetrating thermo and pH stimuli responsive polymer networks of PAAc/PNIPAAm grafted onto PP. Macromol Mater Eng. 292 1176-1188. 

BIG Bignotti, F., Pence, M., Sartore, L., Peroni, I. Mendichi, R., and Casolaro, M., Synthesis, characterisation and solution behaviour of thermo- and pH-responsive polymers bearing L-leneine residues in the side chains, Polymer, 41, 8247, 2000. 

Schmaljohann D (2006) Thermo-and pH-responsive polymers in drug delivery. Adv Drug Deliv Rev 58 1655... 

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