当前位置: X-MOL 学术ACS Appl. Polym. Mater. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Intermolecular Hydrogen Bonding between Poly[(R)-3-hydroxybutyrate] (PHB) and Pseudoboehmite and Its Effect on Crystallization of PHB
ACS Applied Polymer Materials ( IF 4.4 ) Pub Date : 2020-08-31 , DOI: 10.1021/acsapm.0c00758
Changhao Liu 1 , Meng Jia 2 , Jing Qu 3 , Isao Noda 1, 4 , D. Bruce Chase 1 , Reva Street 1 , John F. Rabolt 1
Affiliation  

In the present study, we focused on the intermolecular H-bonding interactions of poly[(R)-3-hydroxybutyrate] (PHB) with an inorganic material, pseudoboehmite (PB), and their effect on PHB crystallization. Noncrystallizable atactic PHB and crystallizable isotactic PHB (a-PHB and i-PHB) ultrathin films were spin-coated on a PB substrate, as well as an aluminum oxide (AO) and a gold substrate for comparison. Infrared reflection–absorption spectroscopy (IRRAS) data show an absorption peak in the carbonyl region located at 1724 cm–1 for a 2.8 nm a-PHB film deposited on PB. A peak at this frequency, often observed for thick bulk crystalline i-PHB films, was not observed for a 1.4 nm a-PHB film deposited on a gold or AO substrate, indicating that the 1724 cm–1 peak observed for a-PHB on PB is not due to a geometric confinement effect or crystallization but due to the existence of intermolecular H-bonding (H-bondinter) between −C═O of a-PHB and −OH from PB. Supercooled, amorphous i-PHB was also found to exhibit the same H-bondinter with PB. It was found that a PB surface significantly modified the crystal orientation and morphologies of the films. Grazing incident wide-angle X-ray diffraction (GIWAXD) data show that the crystallites in i-PHB on PB are randomly oriented, whereas those on AO are predominantly edge-on oriented. Polarized optical microscopy (POM) images show spherulites for i-PHB on AO, whereas no spherulites were observed for i-PHB on PB. This study demonstrates a novel method of using PB to modulate the crystallization behavior of PHB thin films.

中文翻译:

聚[(R)-3-羟基丁酸酯](PHB)与假勃姆石之间的分子间氢键及其对PHB结晶的影响

在本研究中,我们重点研究了聚[(R)-3-羟基丁酸酯](PHB)与无机材料假勃姆石(PB)的分子间H键相互作用及其对PHB结晶的影响。将不可结晶的无规PHB和可结晶的等规PHB(a-PHB和i-PHB)超薄膜旋涂在PB基板上,以及氧化铝(AO)和金基板上进行比较。红外反射吸收光谱(IRRAS)数据显示,沉积在PB上的2.8 nm a-PHB膜的羰基区域的吸收峰位于1724 cm –1处。在厚的块状i-PHB晶体中经常观察到该频率下的峰值,而在金或AO衬底上沉积的1.4 nm a-PHB膜则未观察到此峰,表明1724 cm –1关于PB A-PHB观察到的峰是不是由于几何约束效果或结晶,但是由于分子间氢键(H键的存在帧间一个-PHB的-C = O和-OH从PB之间)。过冷,非晶i PHB也被发现表现出相同的H-键与PB。发现PB表面显着改变了膜的晶体取向和形态。掠入射的广角X射线衍射(GIWAXD)数据表明,PB上i-PHB中的微晶是随机取向的,而AO上的微晶则主要是边沿取向的。偏光显微镜(POM)图像显示AO上i-PHB的球晶,而PB上未观察到i-PHB的球晶。这项研究表明使用PB来调节PHB薄膜的结晶行为的一种新方法。
更新日期:2020-08-31
down
wechat
bug