摘要
利用微悬臂梁传感技术研究了巯基化的聚N-异丙基丙烯酰胺(HS-PNIPAM)在微悬臂梁金面上的自组装过程.由于大分子的构象变化改变了分子间的相互作用,导致微悬臂梁的表面应力改变,使微悬臂梁发生弯曲.通过光学方法实时读出微悬臂梁的弯曲信号,得到HS-PNIPAM的自组装动力学曲线.通过对不同分子量HS-PNIPAM的实验结果分析表明:HS-PNIPAM在自组装过程中存在三个阶段,分别对应不同的分子构象.第一阶段为物理吸附阶段,第二、三阶段为伴随着分子构象变化的化学吸附阶段.吸附曲线符合Langmuir等温吸附.分析结果还显示HS-PNIPAM的表面吸附速率κ远小于小分子的吸附速率,并与分子量成负指数关系;HS-PNIPAM的自组装时间远大于小分子的自组装时间,并与分子量成正比;底物表面应力的改变与HS-PNIPAM的分子量成线性关系.
A microcantilever sensor platform is used for detecting the self-assembly of poly-（N-isopropylacrylamide） （HS-PNIPAM） on gold surface. The change of the interaction between molecules caused by conformation transition will change the surface stress of the microcantilever which causes its bending. The kinetic curves of self-assembly can be obtained by real-time monitoring the deflection of the microcantilever using the optical lever read-out technique. HS-PNIPAMs of different molecular weight were used to study the self-assembly process, and the results showed that the kinetic carves can be divided into three stages corresponding to different conformations, respectively. The first stage cor responds to physical adsorption of HS-PNIPAM on gold-coated side. The second and third stages correspond to chemical adsorption on gold-coated side with conformation transition. The kinetic curves fit Langmuir adsorption isotherm well. The results also show that the reaction rate κ of HS-PNIPAM is far less than that of small molecules and decreases exponentially with the molecular weight; while the time of HS-PNIPAM＇ s self-assembly is far greater than that of small molecules and proportional to the molecular weight. The change of the surface stress is linear to the molecular weight of HS-PNIPAM.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第9期6122-6127,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10732080,20674078和10872191)资助的课题~~
关键词
微悬臂梁
聚N-异丙基丙烯酰胺
自组装
构象转变
microcantilever
poly（N-isopropylacrylamide）
self-assembly
conformation transition
