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首页> 外文期刊>Polymers for advanced technologies >Time‐delayed photo‐induced depolymerization of poly(phthalaldehyde) self‐immolative polymer via in situ formation of weak conjugate acid
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Time‐delayed photo‐induced depolymerization of poly(phthalaldehyde) self‐immolative polymer via in situ formation of weak conjugate acid

机译：通过弱缀合酸的原位形成聚（邻苯二甲酸盐）自我侵略性聚合物的时间延迟光诱导的脱聚

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>Poly(phthalaldehyde) (PPHA) can be used as a structural material in transient devices and photo‐catalytically depolymerized at the end of device life by the use of a photo‐acid generator (PAG). However, device degradation requires the presence of a radiation source at the end of device mission. It has been found that the onset of PPHA depolymerization after PAG photo‐exposure can be delayed by incorporation of a particular weak bases in the PPHA/PAG mixture. This method of delayed PPHA depolymerization allows for PAG activation prior to or during device deployment when the device is under full user control. The basicity of specific lactams and amides was found to slow the PPHA depolymerization, giving the transient device a longer but finite mission lifetime. The weak base reacts with the photo‐generated strong acid to form a weak conjugate acid, which reacts more slowly with PPHA to extend the onset of PPHA depolymerization. The addition of a molar excess of specific lactams or amides, with respect to PAG, maintains PPHA stability and mechanical properties for more than 80?minutes after photo‐exposure at room temperature. The amide or lactam mediated acid activation of PPHA follows first‐order kinetics. The time delay of PPHA depolymerization can allow for prelaunch photo‐exposure and eliminates the need for postmission photo‐exposure where reliable light‐sources may not be available.
机译： > Poly（邻苯二甲醛）（PPHA）可以用作瞬态装置中的结构材料，并通过使用光酸发生器（PAG）在器件寿命结束时光催化解聚。然而，设备劣化需要在设备任务结束时存在辐射源。已经发现，通过在PPHA / PAG混合物中掺入特定的弱碱，可以延迟PPHA解聚后的PPHA解聚。这种延迟P​​PHA解聚方法允许在设备处于完全用户控制时在设备部署之前或期间的PAG激活。发现特异性内酰胺和酰胺的碱度慢慢促使PPHA解聚，使瞬态装置更长但有限的任务寿命。弱碱与光产生的强酸反应以形成弱缀合物酸，其用PPHA更慢地反应PPHA解聚的发作。相对于PAG，添加摩尔过量的特异性内酰胺或酰胺，在室温下光曝光后将PPHA稳定性和机械性能保持超过80Ω分钟。酰胺或内酰胺介导的PPHA酸活化遵循一阶动力学。 PPHA解聚的时间延迟可以允许预先吸收光曝光，并消除对患者光曝光的需求，其中可靠的光源可能不可用。

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