摘要
牺牲层法是制备自支持膜的一种常用方法,但是能在近红外光下降解的牺牲层尚未见报道。我们制备了一种能在980 nm近红外光下降解的层层组装膜,这种膜由含有带正电的邻硝基苄脂基团的季铵盐聚合物(PNBA-TEA),聚苯乙烯磺酸钠(PSS)、支化聚乙烯基亚胺(bP EI)和带负电的稀土上转换纳米粒子(UCNPs),构成结构为[(PNBA-TEA/PSS)*2/(b PEI/UCNPs)*3]*2的聚电解质复合物膜。该膜中的UCNPs可以将近红外光原位转化成紫外光,而PNBA-TEA又可在上述紫外光下降解并生成带负电的光解产物,该光解产物与PSS之间的静电排斥力能导致[(PNBA-TEA/PSS)*2/(b PEI/UCNPs)*3]*2复合膜的完全解离。当把[(PNBA-TEA/PSS)*2/(b PEI/UCNPs)*3]*2复合膜作为牺牲层,并在其上通过层层组装的方法继续生长50个周期的聚烯丙基胺盐酸盐(PAH)/聚丙烯酸(PAA)薄膜,可在近红外光照射后得到大面积且无缺陷的(PAH\PAA)*50自支持膜。近红外光可降解的牺牲层降解条件温和,并且可以非接触式作用,避免了在溶液中浸泡以实现降解的方法对上层膜结构可能造成的损伤,可以在未来运用于制备多种自支持膜。
It remains a challenge to fabricate sacrificial films that are stable in most of solvents and can be readily decomposed on demand. Here we fabricated a near-infrared(NIR) light decomposable sacrificial film by layer-by-layer(LbL) assembly of UV-light-decomposable poly((4-(2-bromoethoxy)-5-methoxy-2-nitrobenzyl acrylate) triethylammonium bromide)(PNBA-TEA), poly(sodium 4-styrene-sulfonate)(PSS), branched polyethyleimine(bPEI) and lanthanide-doped upconversion nanoparticles(UCNPs). In the [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films, UCNPs can convert NIR light into UV light, which can decompose PNBA-TEA. After immersing the NIR light-irradiated [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films in 0.1 M aqueous NaHCO_3 solution, the entire films will disintegrating because of the repulsive force between the negatively charged photoproduct of PNBA-TEA and PSS. Lb L-assembled(PAH/PAA)*50 films deposited on top of the NIR-light-decomposable [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films can be conveniently released to produce large-area and defect-free(PAH/PAA)*50 free-standing films. Because of the satisfactory stability and on-demand decomposable property, the [(PNBA-TEA/PSS)*2/(bPEI/UCNPs)*3]*2 films are promising as sacrificial layers for the fabrication of various free-standing films.
引文
[1]Bao,C,Y.;Jiang,Y,J.;Sun,J,Q.Langmuir,2016,32,3393