简介:ChloridecontentandthepHvalueoftheporesolutionintheneighborhoodofsteelreinforcementaredecisiveparametersforinitiationandrateofcorrosion.Theporesolutionofcementmortarandhardenedcementpastehasbeenexpressedfromtheporespacebyhighpressureintheinvestigation.Theinfluenceofthewater-cementratio,age,andadditionofchloridetothefreshmixonchloridecontentintheporesolutionhasbeendeterminedbyionchromatography.AtthesametimethepHvalueoftheporesolutionhasbeendetermined.Thedissolvedchloridecontentdecreaseswithincreaseinthewater-cementratio.Theamountofboundchlorideincreaseswithtime,butitdecreaseswithdecreasingcontentofdissolvedchlorideintheporesolution.Asignificantinfluenceofcarbonationonthedissolvedchloridecontentoftheporesolutionhasbeenobserved.Withcompletecarbonation,thedissolvedchloridecontentincementmortarandhardenedcementpasteincreasesbyafactorbetween2and12.Theboundchloridedecreasesby27%-4%.Asexpected,thepHvaluedecreasesfromaround13.2toaslowas8.0duetocarbonation.ItcanbeconcludedthatcarbonationnotonlylowersthepHvaluebutliberatesboundchloride.Thisisoneobviousreasonwhythecombinedactionofchloridepenetrationandcarbonationacceleratessteelcorrosionandshortenstheservicelifeofreinforcedconcretestructures.
简介:AtheoreticalinvestigationonthepH-inducedswitchingofmixedpolyelectrolytebrusheswasperformedbyusingamoleculartheory.TheresultsindicatethattheswitchingpropertiesofmixedpolyelectrolytebrushesaredependentonthepHvalues.AtlowpH,negativelychargedchainsadoptacompactconformationonthebottomofthebrushwhilepositivelychargedchainsarehighlystretchedawayfromthesurface.AthighpHvalues,theinversetransformationtakesplace.TheroleofpHdeterminingthepolymerchainsconformationandchargebehaviorofmixedpolyelectrolytebrusheswasanalyzed.Itisfoundthatthereexistsamechanismforreducingstrongelectrostaticrepulsions:stretchingofthechains.TheH+andOH-unitsplayamoreimportantroleascounterionsofthechargedpolymersdo.ThecollapseofthepolyelectrolytechainsfordifferentpHvaluescouldbeattributedtothescreeningoftheelectrostaticinteractionsandthecounterion-mediatedattractiveinteractionalongthechains.
简介:胶体的水晶模板或蛋白石与一包装结束以脸为中心立方(fcc)格子被准备从单音由垂直沉积驱散聚苯乙烯(PS)范围。为单体先锋的渗入的提供的空空格压克力填写了的模板从随后的copolymerization每硫酸盐,以及微胶化吃了酸,压克力酰胺和铵。样品为完全移开PS范围形成PAM反的蛋白石水疗院胶化(IOHPAM)或PAM/PAA反的蛋白石水疗院胶化(IOHPAM/PAA)沉浸于dimethylbenzenephotonic晶体。PS范围坐飞机被代替范围,它通过窗户互连对方。对为IOHPAM和IOHPAM/PAA电影有二座山峰的pH表演的回答的学习,而是IOHPAM/PAA达到顶点到更高的pH的移动,和山峰与AA内容是独立的。
简介:新奇tripyridylporphyrin单体,5-[4-[2-(acryloyloxy)ethoxy]苯基]-l0,l5,20-tris(4-pyridyl)porphyrin(TrPyP),被综合并且有acrylamide(AM)到的polymerized准备恐水病地联系水溶性的聚合物PAM-TrPyP。卟啉pendants的聚集行为被调查由紫外可见并且荧光系列。聚合物在甚至显示恐水病的协会的一个强壮的趋势冲淡解决方案。与增加集中,407nm的从416nm的Soret乐队变化的最大的吸收波长,和荧光为展览节制集中熄灭的内部过滤器效果改正了。所有结果显示那-卟啉pendants的相互作用在卟啉的PAM-TrPyP,和H总数的协会起一个关键作用主要在集中的答案被形成。在另一方面,散布的动态光(DLS)和传播电子显微镜学(TEM)被用来随集中增加在macromolecular集会的尺寸和结构跟随变化。聚合物聚集符合构造因此从松开的像泡的形态学改变到稳固的水珠。当答案的pH价值减少到4.3时,卟啉pendants上的pyridine一半能是protonated,在macromolecular矩阵形成的H总数被静电的排斥相互作用破坏。
简介:Inthispaper,itwasdiscoveredthatanovelpH-sensitivecopolymerofN-isopropylacrylamide(NIP)andN-(3-dimethylaminopropyl)methacrylamide(DMAPM)couldbegottenbypolymerization.ThephasetransitionpH(pHtr)ofP(NIP-DMAPM)polymerwasfoundtobe7.4at37℃.ThepolymerwasprecipitatedoutofwateraboveacriticalpH=7.4andre-dissolvedbelowpH----7.4.Thecharacteristicofthispolymermadeitpossibletocarryouttheimmunochemicalstepsofanimmunoassayinatruesolutionandthentoquicklyseparatetheresultingproductfromthereactionmixture.Inacompetitivefluorescenceimmunoassay,thestandardrabbitIgGandrabbitIgGimmobilizedonP(NIP-DMAPM)firstcompetitivelyreactedwiththefluoresceinisothiocyanate(FITC)labeledantibody,thenthepHofsolutionwasadjustedabovethepHtrofpolymertoprecipitatethepolymer-immunecomplex,andthepolymer-immunecomplexprecipitatewasseparatedandre-dissolvedbytheadjustmentofpH,finallytheFITC-labeledantibodyintheimmunecomplexwasquantifiedbyfluorescencemeasurement.ThecalibrationgraphforrabbitIgGwaslinearovertherangeof100-1000ng/mLwithadetectionlimitof11ng/mL.Themethodisrapid,sensitiveandsimple.OwingtoneutralpHtrofP(NIP-DMAPM),thedamagetoantigen-antibodyimmunecomplexwasgreatlydecreasedinthecourseofseparation.Inaddition,asandwichenzyme-linkedfluorescenceimmunoassaymethodforthedeterminationofhumanIgGwasalsodeveloped,showingthatthepH-sensitivephaseseparatingimmunoassaycouldbeperformedinthecompetitivemethodaswellasthesandwichmethod.
简介:新pH应答的糖类hydrogels被设计并且准备了使用curdlan衍生物(curdlan-Boc-histidine,杂种狗--他的)。杂种狗--他的hydrogels拥有了高度多孔的结构。杂种狗的胀大的比率--他与Boc-histidine的替换的度增加的hydrogels组织。并且0.5mol/LNaCl的增加挑起了杂种狗的胀大的比率的锋利的减小--他的hydrogels。牛的浆液白朊(BSA)能高效地被包含进杂种狗--他的hydrogels。而且,在从杂种狗的不同pH价值的BSA的版本侧面--他的hydrogels是显著地不同的。这些hydrogels在cytotoxicity试金显示出好biocompatibility。杂种狗--他的hydrogels具有在象蛋白质交货系统那样的生物医学的应用的大潜力。
简介:WiththedecreaseofpHvaluefrom8.45to–1.0,theUV-Visabsorptionandfluorescentspectraof1,2-bis(4-pyridyl)ethylene(BPE)tookonthesamechangingtrendatfourdifferentsuccessivepHstages:8.45―7.20,7.20―5.62,5.62―2.60,and2.60―-1.0,namely,nochange,decrease,increase,anddecreaseagain.Amongthese,inarangeof7.20―5.62,thefluorescencewavelengthblueshiftedfrom418to359nm,buttheUV-Visabsorptionwavelength,incontrast,redshiftedfrom285to298nm.ThefluorescenceintensityofBPEhadadropeventoquenchuponadeclineinthepHvaluefrom2.60to–1.0probablyowingtoitscation-πinteractiontoreducetheπelectronclouddensityofBPE.Twodissociationconstants,pKa1(4.30±0.01)andpKa2(5.65±0.04),wereobtainedbasedonfluorescencedata.ThechangesoffluorescencespectraindicatethatBPEhas'off-on-off'switchbehavior.ThefluorescentspectraofBPEwerenearlyindependentonthepresenceofα-andβ-cyclodextrins.