Bairi Partha, Chakraborty Priyadarshi, Shit Arnab, Mondal Sanjoy, Roy Bappaditya, Nandi Arun K
Polymer Science Unit, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700 032, India.
Langmuir. 2014 Jul 1;30(25):7547-55. doi: 10.1021/la500890r. Epub 2014 Jun 18.
5,5'-(1,3,5,7-Tetraoxopyrrolo[3,4-f]isoindole-2,6-diyl)diisophthalic acid (PMDIG) is used to produce a supramolecular hydrogel via acid-base treatment. The field emission scanning electron micrograph and atomic force microscopy micrographs exhibit a fibrillar network structure from intermolecular supramolecular interaction, supported from Fourier transform infrared (FTIR) and UV-vis spectra. The fluorescence intensity of the PMDIG gel is 16 times higher than that of the sodium salt of PMDIG with a 42 nm red shift of the emission peak. Upon addition of an anilinium chloride solution to the PMDIG gel, it transforms into the sol, and when a solid ammonium persulfate is spread over it, a stable hydrogel is produced. The co-assembled PMDIG-polyaniline (PANI) gel exhibits a fibrillar network morphology, and the co-assembly is formed by the supramolecular interaction between the polyaniline (donor) and the PMDIG (acceptor) molecules, which is evident from FTIR spectra and wide angle X-ray scattering results. The UV-vis spectrum of the PMDIG-PANI hydrogel exhibits the characteristic peaks of polaron band transitions of the doped PANI. The PMDIG-PANI co-assembled hydrogel has a 51-fold higher storage modulus, a 52-fold higher elasticity, a 1.4-fold increase in stiffness, and a 5-fold increase of fragility compared to the values of the PMDIG hydrogel. The PMDIG-PANI xerogel exhibits a 4 order of magnitude increase in dc conductivity compared to that of PMDIG, and the I-V characteristic curve exhibits a rectification property under white light illumination showing photocurrent rectification, a new phenomenon reported here for the supramolecular gel systems. A dye-sensitized solar cell fabricated with an ITO/PMDIG-PANI/graphite device shows a power conversion efficiency (η) of 0.1%. A discussion of the mechanism of gel formation and the sol state of the PMDIG-aniline system is included considering the contact angle values of the xerogels.
5,5'-(1,3,5,7-四氧代吡咯并[3,4-f]异吲哚-2,6-二基)二间苯二甲酸(PMDIG)通过酸碱处理用于制备超分子水凝胶。场发射扫描电子显微镜图像和原子力显微镜图像显示，分子间超分子相互作用形成了纤维状网络结构，傅里叶变换红外光谱(FTIR)和紫外可见光谱也证实了这一点。PMDIG凝胶的荧光强度比PMDIG钠盐高16倍，发射峰红移42nm。向PMDIG凝胶中加入氯化苯胺溶液后，它会转变为溶胶，当在其上铺展固体过硫酸铵时，会产生稳定的水凝胶。共组装的PMDIG-聚苯胺(PANI)凝胶呈现出纤维状网络形态，共组装是由聚苯胺(供体)和PMDIG(受体)分子之间的超分子相互作用形成的，FTIR光谱和广角X射线散射结果证明了这一点。PMDIG-PANI水凝胶的紫外可见光谱显示了掺杂聚苯胺的极化子带跃迁的特征峰。与PMDIG水凝胶的值相比，PMDIG-PANI共组装水凝胶的储能模量高51倍，弹性高52倍，刚度增加1.4倍，脆性增加5倍。与PMDIG相比，PMDIG-PANI干凝胶的直流电导率增加了4个数量级，I-V特性曲线在白光照射下呈现整流特性，显示出光电流整流，这是本文报道的超分子凝胶体系的一个新现象。用ITO/PMDIG-PANI/石墨器件制备的染料敏化太阳能电池的功率转换效率(η)为0.1%。考虑到干凝胶的接触角值，对PMDIG-苯胺体系的凝胶形成机理和溶胶状态进行了讨论。
