彈性是聚合物的一種重要性質(zhì)，過去百年不斷有科研人員試圖探索出一套可以量化預(yù)測(cè)材料彈性的方法，但是聚合物內(nèi)存在諸多缺陷和一些影響材料彈性的未知因素使得這項(xiàng)研究工作變得異常困難，但是最近MIT的科研人員取得了重大突破，以水凝膠網(wǎng)絡(luò)聚合物為例，建立一種方法可以分析測(cè)量材料的內(nèi)部缺陷，然后精確地計(jì)算出聚合物網(wǎng)絡(luò)的彈性性能。首先科研人員計(jì)算了單個(gè)缺陷對(duì)材料彈性的影響，然后根據(jù)測(cè)量整個(gè)材料的缺陷獲得材料整體缺陷對(duì)彈性的影響大小，而且理論計(jì)算與實(shí)際測(cè)試結(jié)果相符。通過試驗(yàn)不同材料后，研究人員將理論完善拓展至目前可以預(yù)測(cè)各種聚合物材料的彈性，對(duì)的，目前這套理論可以預(yù)測(cè)各種不同的聚合物材料的彈性性能，這是科研人員首次建立一種理論可以通過缺陷預(yù)測(cè)聚合物的彈性，這項(xiàng)研究成果意義重大，因?yàn)榭梢詭椭芯咳藛T更加精準(zhǔn)地設(shè)計(jì)所需彈性性能的材料。這項(xiàng)研究成果發(fā)布在最新的《Science》雜志上。
參考文獻(xiàn)：Quantifying the impact of molecular defects on polymer network elasticity;Mingjiang Zhong1,2,*, Rui Wang2,*, Ken Kawamoto1,*, Bradley D. Olsen2,?, Jeremiah A. Johnson1,?;Science 16 Sep 2016:Vol. 353, Issue 6305, pp. 1264-1268;DOI: 10.1126/science.aag0184
Abstract
Elasticity, one of the most important properties of a soft material, is difficult to quantify in polymer networks because of the presence of topological molecular defects in these materials. Furthermore, the impact of these defects on bulk elasticity is unknown. We used rheology, disassembly spectrometry, and simulations to measure the shear elastic modulus and count the numbers of topological “l(fā)oop” defects of various order in a series of polymer hydrogels, and then used these data to evaluate the classical phantom and affine network theories of elasticity. The results led to a real elastic network theory (RENT) that describes how loop defects affect bulk elasticity. Given knowledge of the loop fractions, RENT provides predictions of the shear elastic modulus that are consistent with experimental observations.
