TY - JOUR
T1 - A rapid temperature-responsive sol-gel reversible poly(N- isopropylacrylamide)-g-methylcellulose copolymer hydrogel
AU - Liu, Wenguang
AU - Zhang, Bingqi
AU - Lu, William W.
AU - Li, Xiaowei
AU - Zhu, Dunwan
AU - Yao, Kang De
AU - Wang, Qin
AU - Zhao, Chengru
AU - Wang, Chuandong
N1 - Funding Information:
The authors are indebted to the financial supports from the High Tech Research and Development (863) Programme of China (Grant No. 2002AA326100).
PY - 2004/7
Y1 - 2004/7
N2 - Poly(N-isopropylacrylamide) (PNIPAAm) was grafted to methylcellulose (MC) with various feeding ratios using ammonium persulfate and N,N,N′,N′- tetramethyl ethylene diamine as an initiator. FTIR results confirm the formation of PNIPAAm-g-MC copolymers. The temperature responsiveness of copolymer gels was investigated by turbidimetry, dynamic contact angle (DCA), differential scanning calorimetry and dynamic mechanical analysis (DMA). The results indicate that PNIPAAm-g-MC hydrogels are strongly temperature responsive. At lower contents of MC, the lower critical solution temperature (LCST) is decreased, whereas further increasing MC contents raises the LCSTs. It is observed that the phase transition of the hydrogels occurs reversibly within 1min, and near body temperature, a rigid gel can be generated in a certain range of MC content. What is more, the incorporation of MC prevents the syneresis of copolymer hydrogel. DMA measurement reveals that the storage moduli (E′) of the gels increase upon increasing MC contents, and moreover the values of E′ go up markedly above LCST. The copolymer hydrogels hold a promise as a blood vessel barrier by tuning gelation temperature, gelation time and mechanical strength.
AB - Poly(N-isopropylacrylamide) (PNIPAAm) was grafted to methylcellulose (MC) with various feeding ratios using ammonium persulfate and N,N,N′,N′- tetramethyl ethylene diamine as an initiator. FTIR results confirm the formation of PNIPAAm-g-MC copolymers. The temperature responsiveness of copolymer gels was investigated by turbidimetry, dynamic contact angle (DCA), differential scanning calorimetry and dynamic mechanical analysis (DMA). The results indicate that PNIPAAm-g-MC hydrogels are strongly temperature responsive. At lower contents of MC, the lower critical solution temperature (LCST) is decreased, whereas further increasing MC contents raises the LCSTs. It is observed that the phase transition of the hydrogels occurs reversibly within 1min, and near body temperature, a rigid gel can be generated in a certain range of MC content. What is more, the incorporation of MC prevents the syneresis of copolymer hydrogel. DMA measurement reveals that the storage moduli (E′) of the gels increase upon increasing MC contents, and moreover the values of E′ go up markedly above LCST. The copolymer hydrogels hold a promise as a blood vessel barrier by tuning gelation temperature, gelation time and mechanical strength.
KW - Hydrogel
KW - Methylcellulose
KW - Poly(N-isopropylacrylamide)
KW - Temperature responsive
UR - http://www.scopus.com/inward/record.url?scp=1142309722&partnerID=8YFLogxK
U2 - 10.1016/j.biomaterials.2003.09.077
DO - 10.1016/j.biomaterials.2003.09.077
M3 - Article
C2 - 14967533
AN - SCOPUS:1142309722
SN - 0142-9612
VL - 25
SP - 3005
EP - 3012
JO - Biomaterials
JF - Biomaterials
IS - 15
ER -