本研究合成一具有光異構化特性之偶氮苯單體，再經由原子轉移自由基聚合法製備兩性雙團聯共聚物poly(acrylic acid)-block-poly(6-[4- (4’-methoxyphenylazo)phenoxy]hexylmethacrylate) (PAA-b-PAzoMA)。我們利用紫外光-可見光分光光度計探討PAA-b-PAzoMA在不同溶劑中的光異構化行為。PAA-b-PAzoMA在酸性及鹼性水溶液中相較於在THF和DMF中的光異構化反應速率較慢，因為PAA-b-PAzoMA在水溶液中形成微胞結構，偶氮苯鏈段被包覆在微胞的內層，形成立體障礙，致使光異構化的反應速率下降。另外未照射紫外光時的最大吸收峰的波長，在水溶液中相較於在THF和DMF中有藍位移的現象，這代表偶氮苯鏈段在水溶液中是以H-aggregate的形態存在。本研究亦探討PAA-b-PAzoMA在四種不同溶劑中的螢光特性，未照射紫外光時，PAA-b-PAzoMA在水溶液中的螢光量子產率比在THF和DMF中高，在照射紫外光後雖然PAA-b-PAzoMA在各溶劑中的螢光量子產率都有提升，但是在THF和DMF中的螢光量子產率高於在水溶液中，這是由於偶氮苯的順式結構有助於螢光量子產率的提升。而在照射紫外光後，水溶液中偶氮苯的順式結構含量少於在THF和DMF中的含量，所以整體螢光量子產率的提升較少。
本研究亦發現，隨著偶氮苯鏈段的比例越高，光異構化速率越慢，螢光放射的能力越差。

Azobenzene-containing amphiphilic diblock copolymer poly(acrylic acid)-block-poly(6-[4-(4’-methoxyphenylazo)phenoxy] hexylmethacrylate) (PAA-b-PAzoMA) was synthesized via atom transfer radical polymerization (ATRP). We used UV-vis spectroscopy on the PAA-b-PAzoMA solution to investigate the photoresponsive behavior of PAA-b-PAzoMA in various solvents, including aqueous solution with different pH values, THF, and DMF. PAA-b-PAzoMA self-assembled into polymeric micelles with core-shell structure in aqueous solution, resulting in a reduction of the kinetics of photoisomerization. We also investigated the fluorescence emission of PAA-b-PAzoMA in various solvents. The fluorescence emission increased with UV-irradiation because of the formation of cis-isomers. When the molar fraction of azobenzenes in PAA-b-PAzoMA increased, both the photoisomerization rate and fluorescence quantum yield decreased.

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