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Novel dendritic monomers derived from cystamine (Cy) were firstly synthesized in this research. Then, these monomers were used as crosslinkers to prepare three series of thermosensitive hydrogels with 2-(2-methoxyethoxy) ethyl methacrylate (MEMA). The effects of these crosslinkers on the hydrogel’s properties such as swelling behavior, mechanical properties, decomposability and thermoreversibility were investigated and compared with the hydrogel crosslinked by N,N′-bisacrylyl cystamine. The results showed that the equilibrium swelling ratio (SReq) of the hydrogel was affected by the hydrophilic group on the structure of the crosslinker and branch distribution of dendrimer crosslinker. More hydrophilic groups led to higher SReq; however, more complex branch distribution occupied the storage space of water and thus reduced the SReq. The prepared hydrogels all showed apparent thermoreversibility, and the critical gel transition temperature (CGTT) of these hydrogels increased with an increase of hydrophilic group in the crosslinker. Their CGTT showed a range from 26 °C (pure polymer) to 45 °C. More importantly, disulfide bonds in the synthesized hydrogel could be decomposed in the presence of cysteine. This result was confirmed by the change of swelling ratio and mechanical properties before and after they were treated with cysteine. The hydrogels decomposed by cysteine showed higher swelling ratio than the pristine hydrogels. And for mechanical properties, the shear modulus, Young’s modulus and effective crosslinking density of the decomposed hydrogels are lower than the pristine hydrogels. In summary, a thermoresponsive and cysteine-responsive hydrogel has been developed.

Three crosslinkers, poly(ethylene glycol) diacrylate (PEGDA), glycerol ethoxylate triacrylate (GETA) and citric acid-(PEG acrylate)3 (CA-PEGTA) derived from poly(ethylene glycol) (PEG) were synthesized at first. The three series of poly (N-isopropylacrylamide) (PNIPAAm) hydrogels were prepared by photopolymerization with the crosslinkers and compared with a hydrogel based on commercial crosslinker, N,N′-methylene bis-acrylamide (NMBA). The influence of the crosslinker structures and contents on the swelling behaviour, mechanical properties, and drug release of the hydrogels was investigated. The results showed that the hydrogels based on PEGDA and NMBA exhibited the highest and the lowest swelling ratio, respectively. The content of crosslinker of all hydrogel series showed good thermosensitivity and thermo-reversibility. The critical gel transition temperature (CGTT) appeared at 32 °C for the hydrogel based on NMBA, but appeared at about 34 °C for other hydrogels due to higher hydrophilicity of the crosslinker. In the mechanical properties, three-arms crosslinker GETA and CA-PEGTA led to higher mechanical strength than a linear crosslinker PEGDA. A hydrogel based on GETA (NG6) showed the highest shear modulus of 656.9 kPa and Young’s modulus of 1655.0 kPa. The hydrogels containing higher content of crosslinker revealed lower swelling ratio and higher mechanical strength. In the drug release, the hydrogels with higher swelling ratios showed higher drug absorbed. The highest release percentage of caffeine and vitamin B12 for hydrogel based on PEGDA (NP6) could reach 68.3% and 75.4%, respectively. In addition, the bound water and toxicity of the hydrogels were also investigated.

Summary A novel degradable crosslinker, N, N′-bis(acryloyl) cystamine (BACy), was synthesized with cystamine dihydrochloride (Cy) and acryloyl chloride. Then three series of degradable thermosensitive hydrogels with different crosslinker contents were prepared from N-isopropyl acrylamide (NIPAAm), BACy (Bx-series) or N, N′-methylene-bis-acrylamide (NMBA)(Nx-series) or equimolar BACy and NMBA (BNx-series) as crosslinker, and diethoxyacetophenone (DEAP) as photoinitiator under UV-irradiation polymerization. The effect of crosslinker content on the properties of the hydrogels such as swelling behavior and mechanical properties was investigated. At the same time, their degradabilities were investigated by dissolving them into different concentrations of cysteine solution. The results show that the swelling ratios for the Bx-series hydrogels are lower than those for the Nx-series hydrogels. But, after degradation in the cysteine solution, the swelling ratios for the Bx-series hydrogels were greater than those for the Nx-series hydrogels. When the crosslinker content was increased, all values of shear stress (τ), shear modulus (G), and effective crosslinking density (ρX) increased. But, the ρX values for the reduced Bx series and BNx series hydrogels were lower than those for original hydrogels. Results also showed that the ρX values for the Nx series hydrogel were not affected by cysteine. The disulfide bonds of BACy in these novel hydrogels were decomposed (reduced) in the cysteine solution and converted into thiol group. These thiol groups could be used to absorb some metal ions such as silver ion. Hence, the absorption of silver ion for the hydrogel with thiol group was also investigated in this research.

Multifunctional nanoplatforms combined with photodynamic therapy (PDT) and anticancer drugs have shown great promising in cancer therapy. However, their efficacy is limited by the low specificity, low oxygen levels, and a tolerant tumor immune microenvironment. Herein, we developed a biocompatible theranostic nanoplatform (FM@VP) based on co-assembly of a nanocomplex formed by a functional polysaccharide fucoidan and a bioreducible polyamidoamine (PAMAM) dendrimer, a photosensitizer verteporfin (VP), and MnO2 nanoparticles (a tumor microenvironment responsive oxygen evolving nanomaterial) into a multifunctional nanoparticle cluster. The dendrimer-fucoidan polyionic nanocomplex (DFPN) specifically targeted P-selectin-overexpressed triple-negative breast cancer (TNBC) and the tumor-associated vasculature, and was sensitive to glutathione (GSH) in tumor. More importantly, this FM@VP nanocomplex simultaneously overcame tumor hypoxia, suppressed oncogenic signaling, and attenuated tumor-mediated immunosuppression, resulting in improving therapeutic efficacy of PDT while enhancing antitumor immunity and anti-metastasis. This discovery provides a powerful strategy for synergetic cancer targeting/photodynamic/immunotherapy and could serve as a safe clinical translational approach.

This study evaluates the sustained analgesic effect of ketorolac-eluting thermosensitive biodegradable hydrogel in the plantar incisional pain model of the rat hind-paw. A ketorolac-embedded 2, 2'-Bis (2-oxazolin) (BOX) linking methoxy-poly(ethylene glycol) and poly(lactide-co-glycolide) (mPEG-PLGA) diblock copolymer (BOX copolymer) was synthesized as keto-hydrogel based on optimal sol-gel phase transition and in vitro drug release profile. The effect of keto-hydrogel on postoperative pain (POP) was assessed using the established plantar incisional pain model in hind-paw of rats and compared to that of ketorolac solution. Pain and sensory threshold, as well as pain scoring, were evaluated with behavioral tests by means of anesthesiometer and incapacitance apparatus, respectively. Pro-inflammatory cytokine levels (TNF-α, IL-6, VEGF, and IL-1β) around incisional wounds were measured by ELISA. Tissue histology was assessed using hematoxylin and eosin and Masson’s trichrome staining. Ten mg/mL (25 wt%) keto-hydrogel showed a sol-gel transition at 26.4°C with a 10-day sustained drug release profile in vitro. Compared to ketorolac solution group, the concentration of ketorolac in tissue fluid was higher in the keto-hydrogel group during the first 18 h of application. Keto-hydrogel elevated pain and sensory threshold, increased weight-bearing capacity, and significantly reduced the levels of TNF-α, IL-6, and IL-1β while enhanced VEGF in tissue fluid. Histologic analysis reveals greater epithelialization and collagen deposition around wound treated with keto-hydrogel. In conclusion, our study suggests that keto-hydrogel is an ideal compound to treat POP with a secondary gain of improved incisional wound healing.

1-Acrylamidopyrene (AAP) was synthesized for the first time in this study. A series of thermosensitive copolymeric hydrogels were prepared by copolymerization of AAP and N-isopropyl acrylamide (NIPAAm) by UV irradiation. The effect of AAP content in the copolymeric hydrogels on the swelling ratio, mechanical properties, and drug release behavior of the hydrogels was investigated. The swelling ratios decreased from 6.5 to 4.9 (g/g) when the AAP content in the copolymeric hydrogels increased from 0.1 to 0.9 mol% owing to their increasing hydrophobicity. In addition, the thermosensitive behavior obviously diminished with increasing AAP content in the copolymeric hydrogels, but the mechanical properties and cross-linking densities of the hydrogels swollen in ethanol solution were enhanced with increasing AAP content. The swelling ratios of the hydrogels in different solvents were varied with increasing AAP content. The result of caffeine release in the hydrogels showed that when the content of AAP in the hydrogel increased, the caffeine-loading amount decreased; however, their fractional release increased. The corresponding copolymers of the NIPAAm/AAP copolymeric hydrogels were synthesized. The UV absorbance and photoluminescent (PL) behavior of AAP, NIPAAm/AAP copolymeric hydrogels, and their corresponding copolymers in some solvents with different polarities were investigated.

Conventional polyacrylamide hydrogels prepared from the free radical polymerization between acrylamide and N,N′-methylenebisacrylamide (NMBA) have been frequently used in the biochemical technique like the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to resolve protein mixtures. In this study, we have prepared an alternative polyacrylamide hydrogel from the cross-linking of acrylamide and N,N′-bisacrylylcystamine (BACy). In addition, we have compared the BACy-based hydrogel with the NMBA-based polyacrylamide hydrogel for their physical properties such as swelling ratio, shear modulus, crosslink density and morphology. Moreover, we further determined whether BACy-based polyacrylamide hydrogel could be applied to SDS-PAGE and proteomics research. The results showed that this type of hydrogel is capable of separating proteins and facilitates further in-gel protein digestion and the following protein identifications by mass spectrometry. In summary, our study provides a basis for the putative application of BACy-based hydrogels.

This study presents parameter optimization of laser scribing on silver nanowire based conductive thin films and a high-precision Nd–YVO4 (wavelength, 532 nm) laser is used to perform scribing experiments to replace the traditional wet etching process. The laser beam is directly focused on conductive thin films and vaporizes the silver nanowire which is coated on the thin film; consequently it is a non-polluting processes. The main objective of this study is to perform laser scribing experiments to cut off the silver nanowire on the thin film without damaging the flexible PET (Polyethylene terephthalate) substrate. To achieve the desired scribing linewidth, the total degree of freedom (dof) of each factor was calculated without considering the interaction effect among the different control factors. In addition, the Taguchi method was used to study the parameters optimization of the laser scribing experiments. The laser power, laser frequency, focusing position and scribing speed were selected as the four main control factors and the optimum parameters were determined by orthogonal array, main-effects analysis and the analysis of variance theory in the Taguchi method. Under the analysis of 95% CI (Confidence Intervals), the results showed that the validation of the scribed linewidth according to the optimum parameters is correct and this experimental model is reasonably accurate.

Graft copolymerization of silicone monomer—3-(trimethoxysilyl) propyl methacrylate (TMSPMA) grafted onto styrene–butadiene–styrene (SBS; SBS- g-TMSPMA) triblock copolymer was carried out by free radical polymerization, and the improvement of adhesive property of the grafted SBS for glass materials is the major purpose of this study. To gain the optimal reaction conditions and grafting effect, the effect of various factors, such as the monomer ratio and reaction time, on the grafting ratio and grafting efficiency (GE) of SBS- g-TMSPMA graft copolymers were investigated. In addition, various SBS- g-TMSPMA graft copolymers were coated on different substrates based on glass and their tensile strengths that were tested. The optimal graft condition for the SBS- g-TMSPMA was obtained when the molar ratio of TMSPMA to SBS was 1 and reaction time was 4 h. Their grafting ratio and GEreached to a maximum of 56.8% and 60.2%, respectively, and the tensile strength also reached maximum. In this article, we confirm that the higher the grafting ratio, the more the silicone-containing in the graft copolymer. Hence, the –Si–O–Si– bonding between SBS- g-TMSPMA and glass substrate was more intensive and tensile strength was stronger.

Bis[4-(phenyl-isopropyl)phenyl]-4-nitrophenylamine (BiPNPA) (iii) was firstly synthesized via nucleophilic substitution of 4-fluoronitrobenzene (ii) and bis-[4-(phenyl-isopropyl)phenyl]amine (BiPA) (i) in this study, and then compound (iii) was reduced to bis[4-(phenyl-isopropyl)phenyl]-4-aminophenylamine (BiPAmPA) (iv). At last, acrylation of BiPAmPA with acryloyl chloride was performed to obtain a novel bis[4-(phenyl-isopropyl)phenyl]-4-acrylamidophenylamine (BiPAcPA) compound (v). Then, a series of thermosensitive hydrogels were prepared by copolymerization of BiPAcPA and N-isopropyl acrylamide (NIPAAm) by UV irradiation. The effect of BiPAcPA content in the copolymeric hydrogels on the swelling ratio, mechanical properties, and drug release behaviors of the hydrogels was investigated. Results showed that the swelling ratios of the copolymeric hydrogels decreased from 8.2 (g/g) to 5.01 (g/g) when the monomer BiPAcPA content in the copolymeric hydrogel increased from 0.1 mol% to 0.9 mol%. In addition, the thermosensitive behavior obviously decreased with increasing of BiPAcPA content in the hydrogels, but the mechanical properties and crosslinking density of the hydrogel increased with increasing of BiPAcPA content; the caffeine release ratio from 46 % decreased to 29 %. The result of caffeine release also showed that the caffeine-loading amounts decreased with increasing content of BiPAcPA in the hydrogel, but their fractional release increased. In addition, the corresponding copolymers of the copolymeric hydrogels were prepared. Furthermore, the UV absorbance and photoluminescent (PL) behavior of the BiPAcPA, NIPAAm/BiPAcPA copolymeric hydrogels, and their corresponding copolymers in some solvents with different polarities were investigated. The results showed the PL intensity increased with increasing BiPAcPA amounts, especially the wavelength had obvious blue shift phenomenon in THF solvent. The wavelength of UV absorbance and PL emission of BiPAcPA all appeared in visible region. No matter what BiPAcPA monomer, NIPAAm/BiPAcPA hydrogels or NIPAAm/BiPAcPA copolymers, the wavelengths of UV absorbance and PL emission in DMSO solvent are all the same.

Many synthetic strategies of a reversible cross-linker N,N′-bis(acryloyl)cystamine (BACy) involve the typical condensation between the amino group of cystamine and the acyl group of acryloyl chloride in the mixed-phase solvent system. In this study, the synthesis of BACy was performed in pure organic phase during the whole process. The yield and purity of synthesized BACy were comparable to those from aqueous/organic phase procedures. In addition, polymerization of BACy was also carried out by free radical reaction to prepare the self-polymer and hydrogel which were characterized with FT-IR, DSC and UV/VIS spectrophotometer. Notably, the BACy and its self-polymer were both cleavable when exposed to the reducing agents, i.e. 1,4-dithiothreitol (DTT) and 2-mercaptoethanol (β-ME). Interestingly, the reduced product of BACy contains vinyl and thiol groups, which could be further applied to the co-polymerization with other monomeric units. On the other hand, carefully controlled reduction of BACy self-polymer may be used to create the modified polymers with available thiol-end groups for further chemistry. Together, our study provides modified procedure for BACy synthesis and characteristics of BACy self-polymer and hydrogel. Further application of BACy and its self-polymer in developing polymers with additional functionality is anticipated.

In this article, a series of biodegradable cross-linkers, [poly(d,l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(d,l- lactide-co-glycolide), (PLGA-PEG-PLGA), diacrylate] (LGE dA) with different molar ratios of d,l-lactide (LA)/glycolide (GA) in PLGA, were prepared from the corresponding PLGA-PEG-PLGA diol (LGE diol) triblock copolymers and then acrylated with acryloyl chloride. The LGE diols were synthesized through ring-opening polymerization of LA and GA using PEG as an initiator and stannous octoate [Sn(Oct)2] as a catalyst in advance. A series of novel thermosensitive and biodegradable hydrogels were then prepared from N-isopropyl acrylamide (NIPAAm) and LGE dA as a cross-linker. The effect of different molar ratios of LA/GA in PLGA on the swelling ratio and physical properties of the poly(NIPAAm) hydrogels were investigated. The results showed that the swelling ratios of the poly(NIPAAm) hydrogels in deionized water decreased with increasing cross-linker content and increased with increasing GA content in the hydrogel. The compressive modulus and cross-linking density of the hydrogels also increased with an increase in the cross-linker content and molar ratio of LA/GA in the present hydrogel. The hydrogels can be degraded about 60% for the NL50 series of gels, but for NL78 about 53% can be degradable in 1-month biodegradable experiment. © 2012 Wiley Periodicals, Inc. Adv Polym Techn 32: E633–E650, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21307

A series of biodegradable hydrogels were prepared from N-isopropylacrylamide (NIPAAm), acrylic acid (AA), and a biodegradable crosslinker, poly(caprolactone) diacrylate (PCLdA). The effect of the different molar ratios of NIPAAm and AA in the poly(NIPAAm-co-AA) copolymeric hydrogel on the swelling behaviors and physical properties were investigated. The results showed that the swelling ratio in deionized water and in phosphate buffer solution increased with an increase of the content of AA in the copolymeric hydrogel, and the critical gel transition temperature (CGTT) of the copolymeric hydrogel crosslinked with PCLdA was lower than the hydrogel crosslinked with N,N'-methylenebisacrylamide (NMBA). The compressive modulus decreased with an increase of AA content in the copolymeric hydrogels. The gels showed good pH/temperature sensitive behavior. The results also showed that the hydrogel crosslinked with PCLdA has higher crosslinking density (ρx) and higher mechanical strength than the hydrogel crosslinked with NMBA. The influence of the copolymeric composition on the drug release behavior in the poly(NIPAAm-co-AA) hydrogels was also investigated in this study. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A series of interpenetrating polymer network (IPN) hydrogels having higher swelling ratio (SR) and thermosensitivity were synthesized from sodium acrylate (SA) and N-isopropyl acrylamide (NIPAAm) by a two-step method. A series of the porous poly(sodium acrylate -co-1-vinyl–2-pyrrolidone) [poly(SA-co-VP)], (SV), hydrogels were prepared from acrylic acid having 90% degree of neutralization and VP monomer in the first step. The second step is to immerse the SV dried gels into the NIPAAm solution containing initiator, accelerator, and crosslinker to absorb NIPAAm solution and then polymerized to form the poly(SA-co-VP)/poly(NIPAAm) IPN hydrogels (SVN). The effect of the different molar ratios of SA/VP and the content of NIPAAm on the swelling behavior and physical properties of the SVN hydrogels was investigated. Results showed that the SVN hydrogels displayed an obviously thermoreversible behavior when the temperature turns across the critical gel transition temperature (CGTT) of poly(NIPAAm) hydrogel. The pore diameter distributions inside the hydrogel also indicated that the pore sizes inside the SVN hydrogels were smaller than those inside the SV hydrogels. At the same time, the more proportion of SA was added into the hydrogel, the larger pore diameter of the SV hydrogel was formed. The results also showed that the SR decreased with an increase of the VP content in the SV hydrogel and more obviously decreased in the SVN hydrogels. The SVN networks also showed stronger shear moduli than SV hydrogels. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

In this study, we developed a nanoparticle system for drug delivery across the blood–brain barrier (BBB). The nanoparticle consisting of loperamide and poly(lactide-co-glycolide)-poly(ethylene glycol)-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymer were prepared by the nanoprecipitation method; then the nanoparticles were coated with poloxamer 188 or polysorbate 80. The effects of poloxamer 188 or polysorbate 80 on the physicochemical and pharmaceutical properties of the coated nanoparticles were investigated. Loperamide, which does not cross the blood–brain barrier (BBB) but exerts antinociceptive effects after direct injection into the brain, was encapsulated by different polymeric materials and used as a model drug. The in vitro BBB penetration study shows that the surfactant-coated PLGA-PEG-PLGA nanoparticles could have penetration of 14.4–21.2%, which was better than the PLGA-PEG-PLGA nanoparticles (PEP) (8.2%) and the PLGA nanoparticles (PN) (4.3%). The biopsy studies also confirm that the PEP coated by surfactant could increase the penetration. The results of nanoparticles accumulation in brain tissue show that the PEP coated by surfactant had a much higher concentration than both the PEP and the PN. Moreover, the maximal possible antinociception effect (MPE) for the surfactant-coated PEP was 21–35% at 150 min after administering the drug intravenously, which was significantly better than just the PEP (MPE: 11.6%). The results of the formalin test show that the surfactant-coated PEP administered intravenously 150 min prior to the formalin injection could greatly reduce the pain response in the first phase. The results demonstrate that the surfactant-coated PEP could help to deliver loperamide across the BBB.

New poly(amide–imide)s (PAIs) 3a – d and 3 ′ a – d with methoxy-substituted triphenylamine (TPA) units were prepared by the direct polycondensation from various imide ring-preformed dicarboxylic acids 2a – d with 4,4′-diamino-2″,4″-dimethoxytriphenylamine ( 1 ) and 4,4′-diamino-4″-methoxytriphenylamine ( 1 ′), respectively, using triphenyl phosphite and pyridine as condensing agents. For the comparative study, the referenced PAIs 3 ″ a – d without methoxy substituents on the TPA unit were also prepared from 2a – d with 4,4′-diaminotriphenylamine ( 1 ″). All the polymers were readily soluble in many organic solvents and could be solution-cast into tough and flexible polymer films. The glass-transition temperatures ( T g s) of these PAIs ranged from 196 to 298 °C and the 10% weight-loss temperatures were in excess of 445 °C in nitrogen. Cyclic voltammograms of the PAI films cast onto the indium–tin oxide (ITO)-coated glass substrate exhibit one reversible oxidation redox couples at 0.73–0.89 V vs. Ag/AgCl in an electrolyte/acetonitrile solution. The polymer films revealed good electrochemical and electrochromic stability, with coloration change from a pale yellow neutral form to a green oxidized form. After over 100 redox cycles, the polymer films still exhibited good redox and electrochromic reversibility. The 3 and 3 ′ series PAIs exhibited enhanced redox-stability and electrochromic performance as compared to the parent 3 ″ analogs without methoxy substituents on the TPA unit.

A series of novel polyimides based on N,N-di(4-ami- nophenyl)-1-aminopyrene and aromatic or alicyclic tetracarbox- ylic dianhydrides were synthesized. The polymers exhibited good solubility in many polar organic solvents and could afford robust films via solution casting. The polyimides derived from aromatic dianhydrides exhibited high thermal stability and high glass-transition temperatures (333-364 � C). Cyclic vol- tammetry studies of the polymer films showed that these poly- imides are both p and n dopable and have multicolored electrochromic states. For the polyimides derived from alicyclic dianhydrides, they revealed a strong blue-light emission with high fluorescence quantum yields (UPL > 45%) and a marked solvatochromic behavior. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2210-2221, 2011

本研究以縣市層級的「國民教育輔導團」為對象，訪談了四個分布於北、中、南、東縣市的相關行政人員、輔導團員及相關人員。結果發現，目前國家課程與教學的推動面臨四大困境：一、缺乏完善的「行政」與「課程與教學」間的分工與對話機制；二、缺乏課程與教學政策的整合與轉化機制；三、偏重領域學科教學，忽略課程意識的發展；四、對學校層級的課程與教學影響有限。面對此四大 困境，我們建議或許應超越過去「輔導團」為主的課程與教學推動模式，而重新想像一套未來可能的「國家課程與教學推動網絡」。 This study focused on the “Compulsory Education Advisory Groups” at county and city levels, and thereof interviewed administrative staffs, members of the advisory group, and related personnel in the counties and cities of northern, central, southern, and eastern Taiwan. Results showed that, the four obstacles currently facing the National Curriculum and Instruction Promotion Network are: 1) lack of complete division of labor and conversation mechanism between “administration” and “curriculum and instruction” members; 2) lack of integration and transformation mechanism between curriculum and instruction policies; 3) partial emphasis on subject teaching, while neglecting the development of course consciousness; 4) limited influence on curriculum and instruction at the school level. To overcome those four obstacles, this study suggests that the curriculum and teaching promotion model which focuses on the “advisory groups” should be replaced by a new “National Curriculum and Instruction Promotion Network.”

A series of thermosensitive organic–inorganic hybrid gels containing nanosilica or modified nanosilica were prepared from N-isopropylacrylamide (NIPAAm), and N,N′-methylene-bis-acrylamide (NMBA) and nanosilica (AE200) or modified AE200 (mAE200); and NIPAAm, NMBA, 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) as coupling agent and AE200 or mAE200 in this study. The effect of inorganic nanosilica on the swelling behaviors and mechanical properties were investigated by adding different amount of nanosilica and modified nanosilica. Results showed that the swelling ratios of the hybrid gels decrease with increasing nanosilica content. Existence of silane coupling agent would also reduce the swelling ratios of the hybrid gels. Adding coupling agent or nanosilica would improve the gel strength. Modification of nanosilica by grafting amino-silane via sol–gel process was carried out and the effect of addition of modified silica on gel properties was also investigated. Results showed that the hybrid gels containing modified silica would have higher swelling ratios and moduli than those containing unmodified silica. Gels containing both silane coupling agent and silica would have higher crosslinking density because the silica would be better crosslinked with coupling agent. POLYM. COMPOS., 31:1712–1721, 2010. © 2010 Society of Plastics Engineers.

A series of nanocomposite hydrogels (APEAg series gels) were prepared from acrylic acid, poly(ethylene glycol) methyl ether acrylate, and silver nanoparticles through in situ polymerization by UV irradiation. The effect of the content of silver nanoparticle on the properties of the nanocomposite hydrogels was investigated. Results showed that, with increasing of the content of the silver nanoparticle in the hydrogels, the crosslinking density and shear modulus of the hydrogel were not obviously changed, the electrical conductivities of the nanocomposite hydrogels increased, and their initial rate of Escherichia coli inactivation significantly increased, but their adhesive force only slightly decreased. These materials can be assessed as promising bioadhesive patch or wound-dressing material or electrical massage patch.

To improve the wettability or hydrophilicity of the styrene— butadiene—styrene (SBS) triblock copolymer membrane using as transdermal patches, a series of graft copolymers were prepared by grafting hydrophilic monomers onto SBS membrane through ultraviolet irradiation technique. The characterization of the grafted membranes and the influence of various grafting factors on grafting percentage were studied. Infrared and X-ray photoelectron spectroscopy techniques were used to elucidate the surface properties of the grafted membrane. Scanning electron microscopy was used to observe the surface morphology of the grafted membrane. Experimental results showed that the grafting percentage and extent of grafting per area (mg/ cm2) were about linearly increased with an increase of the molar ratio of hydrophilic monomer. In addition, the grafting percentage and extent of grafting per area for the grafted membranes were also approximately linearly increased with increase in irradiation time until 40 min. Decreasing contact angle and increasing equilibrium water content confirmed that the wettability of modified SBS membrane was improved.

A novel structurally asymmetric bis(ether amine) monomer containing trifluoromethyl groups, 1,7-bis(4-amino-2-trifluoromethylphenoxy)naphthalene, was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 1,7-dihydroxynaphthalene in the presence of potassium carbonate in N-methyl-2-pyrrolidone (NMP), followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new fluorine-containing polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two-stage process with thermal or chemical imidization method. The intermediate poly(amic acid)s had inherent viscosities between 0.93 and 1.93 dL/g. Most of the polyimides obtained from both routes were readily soluble in many organic solvents such as NMP and N,N-dimethylacetamide (DMAc). All the polyimides could afford transparent, flexible, and strong films with low moisture absorptions of 0.29-0.69%, low dielectric constants of 2.81-3.23 at 10 kHz, and an ultraviolet-visible absorption cutoff wavelength at 358-423 nm. The glass-transition temperatures (Tgs) (by DSC) and softening temperatures (by thermomechanical analysis) of the polyimides were recorded in the range of 222-271 °C and 210-266 °C, respectively. Decomposition temperatures for 10% weight loss all occurred above 500 °C in both nitrogen and air atmospheres. For a comparative study, some properties of the present polyimides will be compared with those of structurally related ones derived from 1,7-bis(4-aminophenoxy)naphthalene and 1,5-bis(4-amino-2-trifluoromethylphenoxy)naphthalene.

A series of organic–inorganic hybrid thermosensitive gels with three different structures were prepared from N-isopropylacrylamide (NIPAAm), and N, N′-methylenebisacrylamide (NMBA) and tetraethoxysilane (TEOS) [N-IPN]; NIPAAm, 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) as coupling agent and TEOS [NT-IPN]; and NIPAAm, TMSPMA, and TEOS [NT-semi-IPN] by emulsion polymerization and sol–gel reaction in this study. The effect of different gel structures and coupling agent on the swelling behavior, mechanical properties, and morphologies of the present gels was investigated. Results showed that the properties of the gels would be affected by the gel networks such as IPN or semi-IPN and with or without existence of TMSPMA as the bridge chain between networks. The NT-semi-IPN gel had higher swelling ratio and faster diffusion rate because poly(NIPAAm) moiety in the semi-IPN gels was not restricted by NMBA network. However, the IPN gels such as N-IPN and NT-IPN had good mechanical properties and lower swelling ratio, but had a poor thermosensitivity due to the addition of coupling agent, TMSPMA, into the gel system that resulted in denser link between organic and inorganic components. The morphology showed that IPN gels had partial aggregation (siloxane domain) and showed some denser phases. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

A series of thermo-responsive hydrogels were synthesized from N-isopropylacrylamide (NIPAAm), glycidyl methacrylate (GMA), and N, N-dimethyl acrylamide (DMA). The effect of the different monomer ratios of GMA/DMA in the copolymeric hydrogel on the swelling behaviors, physical properties, and drug release behavior was investigated. Results showed that the swelling ratio in deionized water increased with an increase of content of DMA in the copolymeric hydrogel. However, the compressive modulus, crosslinking density, and mechanical strength decreased with increasing DMA content in the copolymeric hydrogel. In addition, the influence of the copolymeric composition on the immobilization of enzyme on the poly(NIPAAm-co-GMA-co-DMA) hydrogel which was used as a support to immobilize trypsin was also investigated. The result showed that the copolymeric hydrogel showed a good immobilized capacity of trypsin. The immobilized trypsin as a ligand of affinity chromatography having fifty three percent activity of trypsin inhibitor in the crude extract of sweet potato can be recovered by affinity chromatography. The molecular weights of the purified trypsin inhibitors are more than 20 kDa by SDS-PAGE.

A series of biodegradable porous hydrogels, based on thermosensitive N-isopropylacrylamide (NIPAAm) and biodegradable crosslinker-polycaprolactone diacrylate (PCLdA) that was synthesized from polycaprolactone diol with acryloyl chloride were prepared by photopolymerization at low temperature. The effect of the crosslinker content and gelation method on the swelling behaviors and physical properties for the poly(NIPAAm) hydrogels was investigated. Results showed that the swelling ratio of the gel in deionized water decreased with an increase of the content of polycaprolactone (PCL) segment in the poly(NIPAAm) hydrogels. The properties of the gels crosslinked with PCLdA were compared with those crosslinked with N, N′-methylenebisacrylamide (NMBA). The results showed that the critical gel transition temperatures (CGTT) of the gels crosslinked with PCLdA were lower than those of the gels crosslinked with NMBA due to the hydrophobicity of the PCL segment. The results also showed that the gels crosslinked with PCLdA had higher mechanical strength and crosslinking density than those gels crosslinked with NMBA. Comparing the porous gels with nonporous gels, the results showed that the swelling ratio and CGTT of the porous gels were higher than those of the nonporous gels, and the transition temperature curve was smoother for the porous gels. The porous gels also exhibited more rapid thermal response and faster degradation rates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

This study was compare of physics and chemical property of Styrene-butadiene-styrene (SBS)/ Acrylic acid (AA) copolymer after thermal polymerization and UV graft-polymerization. The result of this study shows: when the thermal polymerization was used, the grafting percentage of SBS-g-AA rose along with the increase of the AA monomer concentration. The maximum occurred when SBS=0.5g and AA=2.5 x 0.0065mol, then it decreased along with the increase of the AA concentration. The transition ratio and grafting percentage decreased as the concentration of SBS increased; while AA was fixed on 0.0065mol, the maximum grafting percentage occurred by using 1g SBS. The grafting percentage increase along with the increase of reacting time, and it reached the maximum after reacting 3 hours. The water contact angle was lowered from 82o to 58o. Using the UV graft-polymerization, when AA monomer concentration increased, the grafting percentage increased as well; the maximum occurred when AA concentration was 2.88M. Moreover, the grafting percentage was increasing along with the increase of reacting time, but it stopped increasing around 40 minutes reacting time. The grafting percentage of thermal polymerization was higher than UV graft-polymerization. It shows that the swelling ratio of membranes grafted using the UV light was higher than those grafted by thermal polymerization.

In this study, we intend to adjust the charge properties of the poly(N-isopropylacrylamide) [Poly(NIPAAm)] gel by using anionic clay and cationic monomer. Hence, two series of nanocomposite hydrogels bearing different charges were designed from NIPAAm, intercalated mica (IM) (NIM-series) and NIPAAm, IM, trimethyl (acrylamido propyl) ammonium iodide (TMAAI) (NTIM-series), respectively. The mica was first intercalated with different contents of intercalant, trimethyl (acrylamido propyl) ammonium chloride (TMAACl), based on the cationic exchange capacity (CEC) of mica. The effect of the CEC value of IM and IM content on the charge property, swelling behaviors, mechanical properties, and drug-release behaviors of the present gels were investigated. Results showed that the negative charges for NIM series gels decrease with increase in CEC values of the IM (from −11 to −6 mV), the positive charges for NTIM series gels also decrease with increase in CEC values of the IM (from +36 to +18 mV). The swelling behaviors and mechanical properties for the NTIM gels were significantly enhanced by IM content and CEC values of the IM. The microstructures, morphologies, and drug-release behaviors in these two series gels are also investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2277–2287, 2007

A series of antibacterial superabsorbents containing silver nanoparticles based on sodium acrylate (SA), 1-vinyl-2-pyrrolidone-silver ion complex (VP-Ag+) and N, N′- methylene-bisacrylamide (NMBA) were prepared by inverse suspension polymerization. The ascorbic acid (vitamin C) was used as reductant to reduce silver ion complex in the gels through in situ reduction method. The influence of the concentration of VP-Ag+ complex in the superabsorbents on the water absorbency, swelling behavior, and antibacterial effect of Candida albicans was investigated. Results showed that the water absorbency for sodium acrylate and VP copolymeric gel (SV gel) in deionized water was 1016 g H2O/g gel, but the water absorbency for SV-Ag series gel decreased when the silver nanoparticle was added. Results also showed that the antibacterial effect of the superabsorbents increased with an increase of the silver concentration (1 ∼ 10 ppm). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Poly(ethylene glycol) methylether acrylate (PEGMEA) and tetraethylene glycol diacrylate (TEGDA) were first synthesized. The thermosensitive hydrogels were then prepared from N-isopropylacrylamide (NIPAAm), PEGMEA, and three crosslinkers with different structures such as N, N′-methylene-bis-acrylamide (NMBA), TEGDA, and poly(ethylene glycol) dimethacrylate (EGDMA). The influence of polymerization factors such as the kind and amount of crosslinker and initial total monomer concentration on the swelling behavior, gel strength, effective crosslinking densities, and number-average molecular weight between crosslink points ( \(\overline {{M}}_{\rm c}\)) for the present copolymeric hydrogels was investigated. The results indicate that the swelling ratios for the present copolymeric gels decrease with increase in temperature. In addition, the results also showed that the higher swelling ratios for the present gels prepared from TEGDA were obtained due to the larger space between the gel networks. The crosslinking density depends on the swelling ratio and the kind and extent of crosslinker. In addition, the drug release behavior for the present copolymeric gels was investigated.

The influence of positively charged intercalated hydrotalcite (IHT) in the anionic poly(acrylic acid-co-N-isopropyl acrylamide), poly(AA-co-NIPAAm)/hydrotalcite nanocomposite hydrogels on the drug release behavior for the drugs with different charges was investigated in this study. Results show that the loading amount and release ratio of indomethacin are affected by the swelling ratio in saline solution and related to the affinity in the alcohol solution, respectively. The loading amount and release ratio of caffeine are affected by the swelling ratio. The loading amount of crystal violet (CV) increased with an increase of the content of intercalating agent in IHT of the gel but the fractional release of CV in the gels decreases with increase in intercalating agent content. The result of release and loading for phenol red in the hydrogels is contrary to CV.

Three series of copolymeric gels based on N-isopropylacrylamide (NIPAAm) and perfluoroalkyl methacrylate such as 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate (OFPMA), 4,4,5,5,6,7,7,7-octafluoro-2-hydroxy-6-(trifluoromethyl)heptyl methacrylate (OFHHMA), and 3,3,4,4,5,6,6,6-octafluoro-5-(trifluoromethyl)hexyl methacrylate (OFHMA), were prepared by emulsion polymerization. The effect of perfluoroalkyl methacrylate and sodium lauryl sulfate (SLS), which can act as a surfactant and a pore-forming agent, on the equilibrium swelling ratio and mechanical properties of the present hydrogels was investigated. Results show that hydrophobic monomers made the swelling ratio of the gel decrease and the mechanical property of the gel increase; however, SLS exhibits a contrary result. In addition, the effect of perfluoroalkyl methacrylate on the drug release behavior was also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4661–4667, 2006

In a previous study, we prepared a series of xerogels based on sodium acrylate (NaA) and 2-hydroxyethyl methacrylate (HEMA, OE = 1) or poly(ethylene glycol) methacrylate (PEGMA, OE = 6) with different oxyethylene (OE) units. The effect of the contents of HEMA and PEGMA in the copolymeric gel on the swelling behavior in deionized water and various saline solutions was studied. Their results showed that the water absorbencies for these two series gels were effectively improved by adding a small amount of HEMA or PEGMA. In this article, a series of novel xerogels based on NaA and hydrophilic monomer poly(ethylene glycol) methyl ether acrylate (PEGMEAn), which was synthesized from acryloyl chloride and poly(ethylene glycol) monomethyl ether with three oxyethylene (OE = 9, 16, 45) chain lengths, were prepared by inverse suspension polymerization. The effects of OE chain length in the copolymeric gel on the water absorption behavior and initial absorption rate for the present xerogels were investigated. Results showed that adding a small amount of PEGMEAn could effectively increase the water absorbency of the gels. In addition, the water absorbency decreased with an increase of the OE chain length in PEGMEAn. The initial absorption rate for the present copolymeric gels increased with increasing OE chain length in PEGMEAn and the content of PEGMEAn in the copolymeric gels. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 927–934, 2006

A series of hybrid nanocomposite hydrogels, based on gelatin and intercalated hydrotalcite (IHT), crosslinked with glutaraldehyde, was prepared in this study. The microstructures of the IHT and sample gels were identified by X-ray diffraction (XRD). Swelling behaviors and physical properties of these hybrid gels were investigated. XRD results indicated that exfoliation of IHT was achieved in the hybrid nanocomposite gels. The results indicated that adding a small amount of IHT could effectively decrease the swelling ratio of the hybrid gels, but adding excess IHT could increase the swelling ratio of the nanocomposite hybrid gels. The crosslinking densities (ρx) of the present gels varied with IHT content and swelling ratio of the gels. The drug release behaviors of these gels were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 500–507, 2006

A series of porous thermoreversible copolymeric hydrogels were prepared from N-isopropylacrylamide (NIPAAm) and hydrophobic monomers such as 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate (OFPMA) and n-butyl methacrylate (BMA) and CaCO3 or poly(ethylene glycol) 8000 (PEG8000) as porosigen by emulsion polymerization. The effect of hydrophobic monomers and porosigens on the fundamental properties, such as equilibrium swelling ratio, swelling kinetics, gel strength, crosslinked densities, etc., and fast swelling–deswelling behavior for the present copolymeric hydrogels were investigated. Results showed that the deswelling rates for the gels porosigened by CaCO3 were more rapid than those gels foamed by PEG8000. Results also showed that the swelling rates for the gel foamed by CaCO3 were higher than those for the gel foamed by PEG8000. At the same time, results also showed that the gels with OFPMA foamed by CaCO3 exhibit a faster swelling–deswelling behavior than those gels with BMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3152–3160, 2006

A series of composite hydrogels containing silver nanoparticle used for bioadhesives were prepared from acrylic acid, poly(ethylene glycol) methyl ether acrylate, and silver nanoparticles through ex situ polymerization. Silver nanoparticles with a narrow size distribution were prepared by the reduction of a silver nitrate solution with ascorbic acid. The influence of the content of the silver nanoparticles in the hydrogels on the equilibrium swelling ratio, mechanical properties, electrical conductivity, and inactivation of Escherichia coli (E. coli) was investigated in this study. The results showed that the swelling ratios of the composite gels were reduced by silver nanoparticles in the gels but were not reduced with an increase in the content of silver nanoparticles. In addition, the crosslinking density and shear modulus of these hydrogels did not increase with an increase in the content of silver nanoparticles. The adhesive force of these hydrogels (the APECAg series) was not obviously changed. Finally, the initial rate of E. coli inactivation for the APECAg series hydrogels showed excellent antibacterial properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3653–3661, 2006

A series of thermoreversible copolymeric hydrogels with various molar ratios of N-isopropylacrylamide (NIPAAm) and hydrophobic monomers such as 2,2,3,3,4,4,5,5-octafluoropentyl methacrylate (OFPMA) and n-butyl methacrylate (BMA) were prepared by emulsion polymerization. The effect of hydrophobic monomer on the swelling behavior and mechanical properties of the present copolymeric hydrogels was investigated. Results showed that the equilibrium swelling ratio and critical gel transition temperature (CGTT) decreased with an increase of the content of hydrophobic monomer, but the gel strength of the gel increased with an increase of the content of hydrophobic monomer. Due to stronger hydrophobicity of OFPMA, the NIPAAm/OFPMA copolymeric hydrogels had lower swelling ratios and higher gel strengths than NIPAAm/BMA copolymeric gels.

A series of superabsorbents based on sodium acrylate (NaA), mica (MI), and N , N ′-methylene-bis-acrylamide (NMBA) were prepared by inverse suspension polymerization. The influences of the type and content of mica such as pure K + -MI and intercalated-MI (IMI) in the composite gels on the water absorbency and the initial absorption rate in deionized water and salt solutions were investigated. Results showed that the water absorbency and initial absorption rate gradually decrease with increasing amounts of pure K + -MI and intercalated-MI. In addition, the water absorbency and initial absorption rate for the gels prepared by intercalated-MI were lower than those prepared by pure K + -MI.

Organic hybrid gels based on poly(N-isopropylacrylamide) and a natural polymer, gelatin, were prepared through two-step crosslinking with genipin or glutaraldehyde. The effects of the gelatin content on the swelling behaviors and physical properties of these hybrid gels were investigated. The results indicated that the swelling ratio decreased with an increase in the content of gelatin in these hybrid gels. The swelling ratio for the gel crosslinked by genipin was significantly smaller than that for the gel crosslinked by glutaraldehyde. The results also showed that the gel crosslinked with genipin had a higher crosslinking density and a higher gel strength. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1092–1099, 2005

A series of nanocomposite hydrogels were prepared from acrylic acid (AA), N-isopropylacrylamide (NIPAAm), and intercalated hydrotalcite (IHT) by photopolymerization. The influence of the intercalating content of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) in HT on the swelling and mechanical properties for poly(AA-co-NIPAAm)/IHT nanocomposite hydrogels was investigated. The results showed that the higher the content of the AMPS-HT was, the higher the swelling ratio of the gels and the higher the content of the intercalating agent was, the lower swelling ratio. It was also demonstrated that the swelling ratio of the gel was not affected by the counterion in HT. The gel strength and crosslinking density were not enhanced by adding AMPS-HT into the gel composition, but the maximum effective crosslink density and shear modulus of the nanocomposite hydrogels were increased with an increase of the content of the intercalating agent in HT. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1572–1580, 2005