Facile Stimuli-Responsive Transformation of Vesicle to Nanofiber to Supramolecular Gel via ω-Amino Acid-Based Dynamic Covalent Chemistry.
This paper reports an interesting type of self-assembly systems based on dynamic covalent bonds. The systems are pH-responsible and reversible, which could be utilized for controlling the morphology transformation of the assemblies. In alkaline conditions, the amine group of 11-aminoundecanoic acid (AUA) can connect with the aldehyde group of benzaldehyde (BA) or 1-naphthaledhyde (NA) by dynamic covalent bond to form a small organic building block accompanied by the morphological transformation from vesicles to fibers. When pH is lowered to a neutral value, the dynamic covalent bonds (imine bonds) can be hydrolyzed, leading to the dissociation of fibers and appearance of spherical aggregates. The transformation was confirmed reversible as fibers appeared again when the pH was changed back to alkaline value. In addition, a reversibly controlled gel was designed based on the nanofiber formation. NaCl, which is capable of greatly enhance the nanofiber density and cross-linking, was used to induce the growth of free-standing gel from free-flowing nanofiber system, and the resultant gel was proven to be pH-reversible.
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Yajie
Y
Wang
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Pengyao
P
Xing
Department of chemistry, College of Science, Agricultural University of Hebei , Baoding 071001, People's Republic of China.
Shangyang
S
Li
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Mingfang
M
Ma
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Minmin
M
Yang
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Yimeng
Y
Zhang
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Bo
B
Wang
Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University , Jinan 250100, People's Republic of China.
Aiyou
A
Hao