PVA/PAA/Fe~(3+)超分子水凝胶的制备及其性能

为提高水凝胶的力学性能并扩展其应用,采用生物相容性良好的聚乙烯醇(PVA)、聚丙烯酸(PAA)为基质材料,以氢键和配位键为物理交联点,制备具有高力学性能的PVA/PAA/Fe~(3+)水凝胶;通过调节溶液中盐酸浓度、Fe~(3+)浓度和水凝胶浸泡时间研究其对水凝胶力学性能的影响,通过溶液的pH值探讨水凝胶的稳定性,通过循环加载-卸载实验评估水凝胶的自恢复性能。研究结果表明:红外光谱表征水凝胶网络结构氢键及配位键已形成;当溶液盐酸浓度为0.2 mol/L、Fe~(3+)浓度为0.09 mol/L、浸泡时间为20 h时,水凝胶力学强度最优,其拉伸强度为12.69 MPa,韧性为41.64 MJ/m~3;将水凝胶做一次循环加载-卸载实验之后,静置240min,其应力、应变恢复率分别达到90%、87.8%。     

可修复水凝胶光子晶体的制备

采用冷冻-解冻法制备物理交联聚乙烯醇(PVA)水凝胶,在常温下可通过简单贴合实现断口自修复。考察了不同冷冻时间和解冻时间对自修复后水凝胶断裂拉伸应力的影响,结果表明,冷冻时间为24 h,解冻时间为1 h,所得水凝胶在自修复后具有最佳机械性能。进一步研究发现,以PVA水凝胶为基体包封180 nm聚苯乙烯(PS)微球制备的凝胶光子晶体(PC)可通过断面涂覆PVA溶液实现常温自修复,且PVA PCs可以制备成任意形状。衍射光谱表征证明了PVA PCs能够对外部压力刺激产生响应。     

电子束辐射制备pH敏感性聚乙烯醇水凝胶

应用电子束辐射交联技术制备了聚乙烯醇接枝丙烯酸(PVA-g-AAc)水凝胶。研究了pH值、AAc单体用量和辐照剂量等因素对PVA-g-AAc水凝胶溶胀率的影响。实验结果表明,在1 697cm-1处,PVA-g-AAc水凝胶的红外光谱图上出现强烈的羰基的C O特征峰,表明AAc成功接枝到PVA分子上;PVA-g-AAc水凝胶的溶胀率随PVA/AAc/H2O中AAc的质量分数和浸泡时间增加而增大;在pH=9.2时,PVA-g-AAc水凝胶具有显著的pH敏感性;辐射剂量为15kGy时,由PVA/AAc/H2O(1/1/20,质量比)混合溶液制备的PVA-g-AAc水凝胶具有较高的溶胀率;辐射剂量为5kGy时,由PVA/AAc/H2O(1/5/20,质量比)混合溶液制备的PVA-g-AAc水凝胶具有较高的溶胀率。     

水凝胶-固定化酶复合物的制备和性能研究

采用原位复合的方法,将固定有葡萄糖氧化酶(GOD)的多孔SiO_2荧光纳米复合粒子复合在具有温度响应的智能水凝胶聚-N-异丙基丙烯酰胺中,制备了水凝胶-固定化酶复合物。利用场发射扫描电镜、红外光谱和DSC差热分析仪等对其进行表征。研究了pH、温度和给酶量对复合物催化性能的影响,获得了复合物的最佳制备条件。研究了在不同温度下复合物对葡萄糖氧化的酶催化"开-关效应"。为研制检测葡萄糖和胆固醇的多参数光纤生物传感器打下了基础。     

基于葡萄糖氧化酶的葡萄糖传感器的研究进展

综述了对葡萄糖具有良好的催化效应且被广泛用于葡萄糖传感器研发当中的葡萄糖氧化酶(GOx)在葡萄糖传感器酶电极中的固定化方法,并分析其对葡萄糖传感器性能的影响;根据连续监测形式将葡萄糖传感器划分成微创式、植入式和无创式,归纳总结了采用不同监测形式的葡萄糖传感器的最新研究进展;最后,对基于GOx的葡萄糖传感器在柔性可穿戴领域的发展前景进行了展望。     

PVA/壳聚糖/淀粉水凝胶的制备和性能

采用反复冷冻-解冻法制备了一系列的PVA/壳聚糖/淀粉水凝胶.测试了共混膜的力学性能、脱水率和溶胀度.结果表明:壳聚糖含量为2.7%的水凝胶具有最大的断裂延伸率,拉伸强度也较高.淀粉和壳聚糖的加入,改变了复合水凝胶的脱水率和溶胀度.     

水凝胶在光纤传感应用方面的研究进展

水凝胶光纤传感器具有不导电、重量轻、抗电磁干扰及良好的生物相容性等优点,因此在生物传感等多个领域得到了广泛应用。综述了水凝胶在光纤传感的3种调制类型,包括强度调制型、相位调制型和波长调制型。最后针对每种类型的光纤传感器列举了其在葡萄糖检测和pH值测量等方面的应用。     

聚乙烯醇对Al2O3薄膜的影响

摘要：以异丙醇铝为原料,采用溶胶凝胶法和浸渍提拉技术在玻璃栽片上进行涂膜并观察聚乙烯醇（PVA）对薄膜的影响．通过热重分析、红外光谱、硬度、原子力显微镜等测试手段研究了PVA加入量对薄膜结构及性能的影响．实验结果表明,随着PVA添加量的增加,制膜液黏度也随之增加．PVA的最佳加入量为质量分数5％的水溶液20mL;加入20mL,5％PVA后的Al2O3膜具有良好的耐热性;薄膜表面均一平整,有较高的孔隙率,并且孔径分布较均匀,所得平均孔径约为50．3714nm;烧结前,添加PVA薄膜的硬度略大于未添加PVA的薄膜;在烧结后,添加PVA与未添加PVA对Al2O3膜的硬度影响不大;玻璃载片与薄膜之间的黏接性能较好．     

PVA/PAA/BC复合水凝胶的制备与性能

利用冰冻-解冻循环法制备聚乙烯醇（PVA）/聚丙烯酸（PAA）/细菌纤维素（BC）复合水凝胶.研究BC与单体丙烯酸（AA）用量对PVA/PAA/BC复合水凝胶的力学性能和溶胀特性的影响,初步探讨PVA/PAA/BC复合水凝胶的pH敏感性.实验结果表明：随着BC添加量的增多,PVA/PAA/BC复合水凝胶的含水率和拉伸强度与PVA/PAA水凝胶相比均有一定程度的提高,SEM表明复合水凝胶的网络交联点增多;加入AA会使复合水凝胶拉伸强度减小,但溶胀性能提高很多.综合考虑,BC添加量为4%,AA添加量为8%时,各项性能均较好.     

原位复合纳米羟基磷灰石／聚乙烯醇水凝胶的制备及性能研究

原位合成方法制备了n—HA／PVA复合水凝胶．通过调节聚乙烯醇、纳米羟基磷灰石和水的含量，制备了不同配比的复合水凝胶．用燃烧实验、TEM、IR和XRD等对材料的组成和结构进行了表征，并测定了水凝胶的力学性质．结果表明，PVA高分子空间三维结构对羟基磷灰石晶体的原位水热生长有一定影响，复合水凝胶中n-HA与PVA有一定键合，两相分布均匀，羟基磷灰石的含量对复合水凝胶的力学强度有很大影响．     

Enhancing the formation of starch-based hybrid hydrogel by incorporating carboxyl groups into starch chains

A novel starch-based hybrid hydrogel was formed by physical and mild steps. Firstly, aqueous solution of a mixture of starch maleic half-ester (SM) and poly(vinyl alcohol) (PVA) was subjected to freezing-thawing cycles to generate a physical functional SM/PVA hydrogel. Subsequently, the SM/PVA/HA hybrid hydrogel was obtained through the alternate soaking process. The structure and morphology of the hydrogels were examined with Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). It was found that the existence of carboxylic groups on SM chains not only enabled SM/PVA hydrogel to be pH-sensitive, but also enhanced the formation of hydroxyapatite in the hydrogel via chelating calcium ions onto the matrix.     

Research on the friction and wear mechanism of Poly(vinyl alcohol)/hydroxylapatite composite hydrogel

Poly(vinyl alcohol)/Hydroxylapatite (PVA/HA) composite hydrogel was prepared with poly(vinyl alcohol) and hydroxylapatite as raw materials, using the method of repeated freezing and thawing. The morphologies of PVA/HA composite hydrogel were observed by means of high-accuracy 3D profiler and scanning electron microscope (SEM). The compressive elastic modulus and the stress relaxation characteristics of PVA/HA composite hydrogel were measured using the flat-head cylinder indenter. The friction and wear tests between PVA/HA composite hydrogel and bovine knee articular cartilage were performed on the micro-tribometer. The worn morphologies of PVA/HA composite hydrogel were observed with environmental scanning electron microscope (ESEM). The results showed that PVA/HA composite hydrogel has the cross-link network microstructure which is similar to that of the natural bovine knee articular cartilages. With the increase of freezing-thawing cycles and the HA content, the degree of cross-link and the crystallization of PVA/HA composite hydrogel both increase, the elastic modulus increases evidently, the rate of stress relaxation is improved and the value of balance stress decreases. The friction coefficient decreases with the increase of the freezing-thawing cycles and the HA content. The more the freezing-thawing cycles are, the earlier the friction coefficient reaches the stable balance value. The friction deformation depth between PVA/HA composite hydrogel and bovine knee articular cartilage is inversely proportional to freezing-thawing cycles and the HA content. The main wear mechanisms of PVA/HA composite hydrogel are plastic flowing and adhesive flaking. The wear severity degree decreases with the increase of freezing-thawing cycles and the HA content. Supported by Key Program of the National Natural Science Foundation of China (Grant No. 50535050), Program for New Century Excellent Talents in University (Grant No. NCET-06-0479) and Natural Science Foundation of Jiangsu Province (Grant No. BK2005403)     

聚乙烯醇-聚丙烯酰胺互穿网络水凝胶的制备及吸附性能

采用聚乙烯醇(PVA)、聚丙烯酰胺(PAM)为原料,戊二醛(glutaraldehyde)为交联剂,制备了一种互穿网络(IPN)水凝胶。用傅立叶红外光谱仪对其结构进行表征,研究了PVA和PAM按不同配比及交联剂的不同用量制备的IPN水凝胶的吸水性和Cu²⁺的吸附性,主要探讨了吸附时间、pH、吸附温度等对吸附Cu²⁺的影响,分析了吸附行为及其动力学特性,并对其吸附机理做出了初步探讨。结果表明：在本实验研究范围内,30wt.% PAM含量的PVA-PAM IPN水凝胶在pH=5时对Cu²⁺的吸附效果最佳;在一定温度范围内,PVA-PAM IPN水凝胶对Cu²⁺的平衡吸附量随温度升高而增大;吸附行为符合准一级和准二级动力学方程,扩散机制为颗粒内扩散和膜扩散双重作用。     

Synthesis and properties of physically crosslinked poly (vinyl alcohol) hydrogels

The present study is an investigation of the properties of poly (vinyl alcohol), which would be a better contact lens material than conventional HEMA in some ways. A transparent PVA hydrogel was prepared from a PVA solution in a mixed solvent consisting of water and a water-miscible organic solvent, DMSO, by the freezing-thawing method. The water content, visible light transmittance, mechanical and swelling properties of the hydrogels were evaluated as a function of PVA concentration and number of freeze-thaw cycles. The results show that the properties of PVA hydrogels depend on the polymer concentration, the number of freeze-thaw cycles and the addition of the organic solvent.     

基于聚苯胺/聚乙烯醇水凝胶的柔性传感器信号解耦算法研究

结合双网络聚苯胺/聚乙烯醇复合水凝胶(PANI/PVA)各向异性的特性,设计了一种"三明治"夹层式结构的柔性传感器,主要用于管道内复杂受力情况的复合测量.并利用有限元软件验证了传感器对三维空间受力的可测性,搭建了标定试验台.因柔性传感器存在个性化参数差异及受力维间耦合等特性,在标定平台上采集了500组数据,涵盖了多方向...     

Fabrication and Characterization of One Interpenetrating Network Hydrogel Based on Sodium Alginate and Polyvinyl Alcohol

One interpenetrating network hydrogel based on sodium alginate(SA) and polyvinyl alcohol(PVA) was synthesized by combining the raw materials of PVA and SA with the double physical crosslinking methods of freezing thawing and Ca~(2+) crosslinking. The PVA-SA composite hydrogel have been characterized by scanning electron microscopy for surface morphology, infrared spectroscopy for investigating the chemical interactions between PVA and SA, X-ray diffraction for studying the PVA-SA composite structure property and thermal gravimetric for understanding the PVA-SA composite thermal stability. The swelling behavior and the degradation rate of the PVA-SA composite hydrogel were studied in simulated gastrointestinal fluid. Using bovine serum albumin(BSA) and salicylic acid as the model drugs, the release behavior of the PVASA composite hydrogel on macromolecular protein drugs and small molecule drug were evaluated. The results showed that the water absorption and degradation ability of the PVA-SA composite hydrogel was much better compared to the pure SA hydrogel or pure PVA hydrogel. The hydrogel exhibited remarkable pH sensitivity and the network was stable in the simulated intestinal fluid for more than 24 h. With the advantages such as mild preparation conditions, simple method, less reagent and none severe reaction, the PVA-SA composite hydrogel is expected to be a new prosperous facile sustained drug delivery carrier.