研究ers at theNational Institute of Standards and Technology(NIST) have developed a new method of 3D printing gels and soft materials.
研究团队利用电子和X射线梁来固化一系列光蛋白，而不是使用紫外线（UV）或可见光来启动其凝胶。这些较短的波长激光器比常规梁更为聚焦，并能够以高水平的结构细节的形式制造凝胶，尺寸小至100纳米（NM）。
The NIST scientists’ newly-developed technique could allow for the creation of complex microscopic structures, such as flexible electrodes, biosensors, or soft micro-robots.
The different methods of photocuring polymers
可光电聚合物开发的最新创新已大大提高了使用软材料3D打印的速度和分辨率。这些新增强的配方使光学光刻和立体光刻（SLA）方法用于创建日益小的物体，其中一些在100nm范围内。
相比之下，传统的软制造方法（例如电子束光刻（EBL））无法跟上，并且需要紧密关注的电子束才能有效运行。尽管EBL通常用于聚合物和凝胶膜的模式，但它仅与激光和材料之间的高度相互作用作用，从而限制了它可以产生的物体的复杂性。
Focused electron beam-induced deposition (3D-FEBID) represents a more innovative 3D printing approach and uses an electron beam to separate the surface of gaseous metal-containing precursors. The experimental technique is capable of creating objects at an ultra-high-resolution but at the cost of being considerably slower than conventional methods.
Similarly, significant progress has been made in the development of deep X-ray lithography, which uses zone plate-focused beams for the precise fabrication of high-aspect-ratio microstructures. The advanced production process causes reduced radiation damage, and this has allowed it to be used within medical applications such as polymerization inside live systems.
Unfortunately, X-ray oriented methods have drawbacks too. At present, the short wavelengths emitted by X-ray beams can only operate in a vacuum, so the liquid in each chamber could evaporate rather than forming a gel. In order to overcome this limitation, the team theorized that using a thin electron-transparent barrier, they could prevent the liquid from evaporating, while allowing the beam to penetrate the gel.
NIST团队基于凝胶的3D打印方法
To effectively deliver focused electron and soft X-ray beams to their liquid solution, the researchers designed a set of closed, fluidic chambers. The devices were equipped with 30–50 nm thin silicon nitride (SiN) membranes, which acted to isolate the liquid from the vacuum of the microscope.
During testing, the chamber was filled with poly(ethylene glycol) diacrylate (PEGDA) 20% w/v aqueous solution, and nine identical membrane windows. By varying only one of the beam’s parameters such as its energy, intensity, step-size, or dwell time, while keeping others locked, the barriers were used to create parts with a range of different feature sets.
After rinsing off the uncured solution, the team used an Atomic Force Microscopy (AFM) to inspect their cross-linked structures. By comparing the height of the sample objects in their hydrated and dry states, the researchers were eventually able to print them consistently and to estimate the size of the gel-based objects without directly measuring them.
更重要的是，该方法被证明能够生产宽100-150nm的结构，使研究人员推测它可用于创建计算机 - 脑接口设备。为了测试其新技术的活电池接口功能，该团队进行了进一步的实验，该实验将SIN膜细胞和PEGDA聚合物暴露于电子束。
Although some of the cells died, the majority were successfully integrated into an electrode. As a result, the team concluded that their method had the potential to be used in creating futuristic microscopic implantable devices, at sizes as small as 50nm. “We’re bringing new tools – electron beams and X-rays operating in liquids – into the 3D printing of soft materials,” concluded lead researcher Andrei Kolmakov.
纳米级的增材制造
Given the range of potential uses that exist for nanoscale 3D printed objects, it’s hardly surprising that scientists have sought to optimize the technology in recent years, and produce ever-smaller objects.
来自University of Daytonhave developed an enhanced, cost-effective method of3D printing nanoscale structures. The Opto-Thermo-Mechanical (OTM) nano-printing technique proved capable of printing at a scale of less than 100nm.
Scientists from theFraunhofer Institute for Microengineering and Microsystems（imm）正在开发使用多光谱光刻的新过程to create nanoscale metal 3D printed structures. Through the project, the team is aiming to fabricate parts with smaller features than those produced using Direct Energy Deposition (DED) processes.
A team from theCalifornia Institute of Technology(Caltech) have使用了两光谱光刻法to 3D print metal structures that are no larger than 100nm. The technique is reportedly capable of making metal features that are “an order of magnitude smaller” than any other metal fabrication process.
The researchers’ findings are detailed in their paper titled “电子和X射线聚焦梁诱导的液体中的交联：使用软材料快速连续3D纳米覆盖和接口，”发表在《 ACS Nano Journal》上。该论文由Tanya Gupta，Evgheni Strelcov，Glenn Holland，Joshua Schumacher，Yang Yang Yang，Mandy B. Esch，Vladimir Aksyuk，Patrick Zeller，Matteo Amati，Luca Gregoratti和Andrei Kolmakov合着。
Nominations for the2020 3D Printing Industry Awards仍然是开放的,让我们知道谁是领导印第安纳州ustry now.
The fourth edition of the3D打印行业Awards Trophy Design Competitionis now underway. Enter your design for the chance to win a CraftBot Flow 3D printer.
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特色图像显示了NIST研究人员的新Nanoscale 3D打印方法的图表。图片通过ACS Nano Journal。
