title: Effect of the molecular architecture on the thermosensitive properties of chitosan-g-poly(N-vinylcaprolactam).
abstract: A series of thermoresponsive copolymers based on chitosan-g-poly(N-vinylcaprolactam) were synthesized by amidation reaction using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride as coupling reagent. The effect of molecular architecture on the thermoresponsive properties of the graft copolymers solutions was studied by varying the chain length of the grafted poly(N-vinylcaprolactam), PVCL, (in the range from 4 to 26 kDa) and the spacing between grafted chains onto the chitosan backbone. The most interesting characteristic of these copolymers is their solubility in water at temperatures below their lower critical solution temperature (LCST). These solutions presented a LCST between 36 and 44 °C, which decreases with the spacing and length of grafted PVCL chains onto the chitosan backbone, in contrast with the limited decrease of the LCST of PVCL above a critical M¯n value around 18 kDa. This behavior offers tangible possibilities for the preparation and application of sensitive bioactive formulations and "smart" drug delivery systems.
authors.affiliation: CIAD - Guaymas, Carret. al Varadero Nacional km 6.6, Guaymas, Sonora 85480, Mexico.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fernández-Quiroz
authors.affiliation: ICTP-CSIC c/ Juan de la Cierva 3, 28006 Madrid and CIBER, Health Institute Carlos III, C/ Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: González-Gómez
authors.affiliation: CIAD - Hermosillo, Carret. a la Victoria km 0.6, Hermosillo, Sonora 83304, Mexico.
authors.forename: Jaime
authors.initials: J
authors.lastname: Lizardi-Mendoza
authors.affiliation: ICTP-CSIC c/ Juan de la Cierva 3, 28006 Madrid and CIBER, Health Institute Carlos III, C/ Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain.
authors.forename: Blanca
authors.initials: B
authors.lastname: Vázquez-Lasa
authors.affiliation: CIAD - Hermosillo, Carret. a la Victoria km 0.6, Hermosillo, Sonora 83304, Mexico; Westfälische Wilhelms Universität Münster, IBBP, Schlossgarten 3, D-48149 Münster, Germany.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Goycoolea
authors.affiliation: ICTP-CSIC c/ Juan de la Cierva 3, 28006 Madrid and CIBER, Health Institute Carlos III, C/ Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: San Román
authors.affiliation: CIAD - Guaymas, Carret. al Varadero Nacional km 6.6, Guaymas, Sonora 85480, Mexico. Electronic address: waldo@ciad.mx.
authors.forename: Waldo M
authors.initials: WM
authors.lastname: Argüelles-Monal
mesh_terms: D002209:Caprolactam / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D048271:Chitosan / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D003692:Delayed-Action Preparations / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009025:Morpholines / Q000138:chemical synthesis / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: C467606:4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride; D003692:Delayed-Action Preparations; D009025:Morpholines; D011108:Polymers; D014867:Water; C086861:poly-N-vinylcaprolactam; D002209:Caprolactam; D048271:Chitosan
keywords: Chitosan; Graft copolymer; Poly(N-Vinylcaprolactam); Thermosensitive properties