Advanced composite structural components in aeronautics are characterized by very high production costs because of their dimensions, complex shapes and expensive forming equipment. For these components, such as horizontal stabilizers and wings, a defect occurrence is often critical because large part of inner surfaces, made of long and tapered narrow tunnels, are not reachable for repair operations. In these cases, the part is rejected with a relevant economic loss and high production costs. For this reason, aircraft constructors plan huge investments for defects avoidance during the forming processes of CFRP and to develop effective, robust and reliable repair tools and methods. Mobile robotics can play an important role, with specific systems capable of moving into narrow channels of wings structures (i.e. multi spar boxes) and repair it in accordance to technical standards. This paper describes an innovative mobile robot architecture for bonded repair scarfing operations on CFRP components. Targeting and responding to the demanding machining requirements, the functional-oriented design approach clearly highlights the advantages of a modular robotic solution. The mobile robotic architecture can be also applied in other fields with similar challenging manufacturing operations for further inspection, detection and machining operations.

A comparison of the machining performance of micro-EDM milling and sinking is proposed considering the fabrication of micro-channels with controlled sloped walls realized in a hardened steel workpiece. Adopting the fine-finishing machining regime for both micro-EDM techniques, the experimental results show that micro-EDM sinking is about 10 times faster than milling in the worst case, though a lack of accuracy in the final micro-features in the former case is detected due to not compensated tool wear. On the contrary, micro-EDM milling provides a better control of the micro-channel dimensions. Finally, a micro-filter mold for medical applications is machined in order to show the potential of the combination of both technologies.

Outline of the presentation:- Overview on mould cavity sensorization in Micro Injection Molding (µIM)- A setup for mould cavity pressure and Temperature sensorization- DAQ system architecture (HW/SW)- Results: Cavity p,T profiles, process and quality optimization- Data processing and integration with µIM Machine - Conclusions

In injection moulding, continuous monitoring of temperature and pressure parameters in the mould cavity is very important for process control and optimization. In the micro injection moulding process, however, it is more difficult to measure the cavity pressure and temperature due to the extremely small sizes involved. In this paper, a novel setup for cavity pressure and temperature measurements is presented: a miniaturized p,T quartz sensor is used to measure both pressure and temperature directly in the middle of the mould cavity and a data acquisition system has been developed in order to collect signals provided by the sensors. It was demonstrated the suitability of the novel setup to micro injection moulding and that it can be easily applied to any micro injection moulding machine.

In this paper a parametric, modular and scalable algorithm allowing a fully automated assembly of a backplane fiber-optic interconnection circuit is presented. This approach guarantees the optimization of the optical fiber routing inside the backplane with respect to specific criteria (i.e. bending power losses), addressing both transmission performance and overall costs issues. Graph theory has been exploited to simplify the complexity of the NxN full-mesh backplane interconnection topology, firstly, into N independent sub-circuits and then, recursively, into a limited number of loops easier to be generated. Afterwards, the proposed algorithm selects a set of geometrical and architectural parameters whose optimization allows to identify the optimal fiber optic routing for each sub-circuit of the backplane. The topological and numerical information provided by the algorithm are then exploited to control a robot which performs the automated assembly of the backplane sub-circuits. The proposed routing algorithm can be extended to any array architecture and number of connections thanks to its modularity and scalability. Finally, the algorithm has been exploited for the automated assembly of an 8x8 optical backplane realized with standard multimode (MM) 12-fiber ribbons.

In the present paper, a numerical approach to model the layer-by-layer construction of cured material during the Additive Manufacturing (AM) process is proposed. The method is developed by a recursive mechanical finite element (FE) analysis and takes into account forces and pressures acting on the cured material during the process, in order to simulate the behavior and investigate the failure condition sources, which lead to defects in the final part geometry. The study is focused on the evaluation of the process capability Stereolithography (SLA), to build parts with challenging features in meso-micro scale without supports. Two test cases, a cantilever part and a bridge shape component, have been considered in order to evaluate the potentiality of the approach. Numerical models have been tuned by experimental test. The simulations are validated considering two test cases and briefly compared to the printed samples. Results show the potential of the approach adopted but also the difficulties on simulation settings.

The aim of the present study is the assessment of the integration of a low cost optical measurement device into a high-precision machine tool for micro manufacturing applications. The measurement system can be effectively integrated into the working volume of different types of machines allowing both tool and workpiece measurements and avoiding its disassembly from the machine stage for off-line measurements and, consequently, reference losses. The fast measurements of tool and workpiece during the machining contribute to increase the accuracy and reduce the overall machining-measurement iterations. The assessment is achieved by a test case where a low cost USB microscope is applied to a micro-EDM machine. The low cost device has been applied for tool electrode measurements and tool wear evaluation after an accuracy enhanced calibration procedure and high performance image processing algorithms, which effectively reduce the lack of the hardware performance. The measurement performance gives a feedback on the deviations of the machined features from nominal geometry and allows their compensations by an adequate machining strategy.

Here novel chromogenic photonic crystal sensors based on smart shape memory polymers (SMPs) comprising polyester/polyether-based urethane acrylates blended with tripropylene glycol diacrylate are reported, which exhibit nontraditional all-room-temperature shape memory (SM) effects. Stepwise recovery of the collapsed macropores with 350 nm diameter created by a "cold" programming process leads to easily perceived color changes that can be correlated with the concentrations of swelling analytes in complex, multicomponent nonswelling mixtures. High sensitivity (as low as 10 ppm) and unprecedented measurement range (from 10 ppm to 30 vol%) for analyzing ethanol in octane and gasoline have been demonstrated by leveraging colorimetric sensing in both liquid and gas phases. Proof-of-concept tests for specifically detecting ethanol in consumer medical and healthcare products have also been demonstrated. These sensors are inexpensive, reusable, durable, and readily deployable with mobile platforms for quantitative analysis. Additionally, theoretical modeling of solvent diffusion in macroporous SMPs provides fundamental insights into the mechanisms of nanoscopic SM recovery, which is a topic that has received little examination. These novel sensors are of great technological importance in a wide spectrum of applications ranging from environmental monitoring and workplace hazard identification to threat detection and process/product control in chemical, petroleum, and pharmaceutical industries.

Smart shape memory polymers (SMPs) can memorize and recover their permanent shape in response to an external stimulus, such as heat, light, and solvent. They have been extensively exploited for a wide spectrum of applications ranging from biomedical devices (e.g., surgical stents and sutures) and implants for minimally invasive surgery to aerospace morphing structures and self-healing materials. However, most of the existing SMPs are thermoresponsive and their performance is hindered by slow response speed, heat-demanding programming and recovery steps. In this manuscript, by integrating scientific principles drawn from two disparate fields that do not typically intersect - the photonic crystal and SMP technologies, we report a new type of SMP that enables unusual "cold" programming and instantaneous shape recovery triggered by exposing the samples to various organic vapors. These stimuli-responsive materials differ greatly from existing SMPs as they enable orders of magnitude faster response, striking chromogenic effects, and room-temperature operations for the entire shape memory cycle, promising for many applications ranging from reusable chromogenic vapor sensors to reconfigurable nanooptical devices. Moreover, this interdisciplinary integration provides a simple yet sensitive optical technique for investigating the intriguing shape memory effects at nanoscale.

The paper presents the design and development of a new robotized assembly system of optical backplanes in high-capacity ICT (Information and Communication Technology) apparatus, mainly used for switching stations and distribution networks. The optical backplane solution consists of several optical fiber ribbons positioned on a planar backplane according to an innovative and optimized full-mesh layout where the overall optical interconnection is partialized into a plurality of different independent sub-circuits. Each optical interconnection sub-circuit consists of optical fiber ribbons with standardized optical and mechanical interfaces and customized components that have to be carefully and precisely assembled in order to achieve connections with low optical power losses. The paper describes the method and the main devices and tools conceived for the automatic assembly of optical interconnection sub-circuits, highlighting the critical aspects and the proposed solutions towards the automatized assembly of the whole optical backplane.

This paper reports on design, fabrication, and characterization of a microfilter to be used in biomedical applications. The microfilter, with mesh of 80 ?m, is fabricated by micro-injection molding process in polymeric material (polyoxymethylene (POM)) using a steel mold manufactured by micro-electrical discharge machining process. The characteristics of the filter are investigated by numerical simulation in order to define a suitable geometry for micro-injection molding. Then, different process configurations of parameters (melt temperature, injection velocity, mold temperature, holding pressure and time, cooling time, pressure limit) are tested in order to obtain the complete part filling via micro-injection molding process preventing any defects. Finally, the component is dimensionally characterized and the process parameters optimized to obtain the maximum filtration capacity.

This paper reports on design, fabrication and characterization of a micro-filter for hearing aid, dialysis media and inhaler. The microfilter is fabricated by micro injection moulding process in polymeric material (Polyoxymethilene - POM) using a steel mould manufactured by micro electrical discharge machining process. A novel filter configuration is proposed and, in the design step, the characteristics of the filter are investigated by numerical simulation in order to define a suitable geometry for micro-injection moulding. Then, different process configuration of parameters (melt and mould temperature, injection velocity, holding time and pressure, cooling time, pressure limit) are tested in order to obtain the complete part filling. Finally the component is dimensionally characterized and the process parameters optimized to obtain the maximum filtration capacity.

Here we report a single-step direct writing technology for making three-dimensional (3D) macroporous photonic crystal patterns on a new type of pressure-responsive shape memory polymer (SMP). This approach integrates two disparate fields that do not typically intersect - thewell-established templating nanofabrication and shape memory materials. Periodic arrays of polymer macropores templated from self-assembled colloidal crystals are squeezed into disordered arrays in an unusual shape memory "cold" programming process. The recovery of the original macroporous photonic crystal lattices can be triggered by direct writing at ambient conditions using both macroscopic and nanoscopic tools, like a pencil or a nanoindenter.Interestingly, this shape memory disorder-order transition is reversible and the photonic crystal patterns can be erased and regenerated for hundreds of times, promising for making reconfigurable/rewritable nanooptical devices. Quantitative insights into the shape memory recovery of collapsed macropores induced by the lateral shear stresses in direct writing are gained through fundamental investigations on important process parameters, including the tip material, the critical pressure and writing speed for triggering the recovery of the deformed macropores, and the minimal feature size that can be directly written on the SMP membranes. Besides straightforward applications in photonic crystal devices, these smart mechanochromic SMPs that are sensitive to various mechanical stresses could render important technological applications ranging from chromogenic stress and impact sensors to rewritable high-density optical data storage media.

In previous research activities, the nanoporous structure SMP has been investigated showing the SMP behavior, the deformation induced by water extraction or mechanical pressure and other action, the recovery action, nanomechanical experimentation, and relate the mechanical deformation state with optical behavior.In studying these nanoporous materials, validated optical, mechanical FEM and Multiphysics models should be a very useful tool for understand the behavior of the SMP photonic crystal. The research activity proposal is focused on knowledge, methods and tools development for nanoporous structures SMP modeling, simulation of mechanical and optical phenomena and behavior.The aim is to formulate a consistent, accurate and reliable framework for numerical prediction of multi-physic (coupled mechanical and optical) behavior of nanoporous SMP structures. These results will be achieved studying and developing a very effective example of multi-physics device and material: a photonic crystal Nanoporous Shape Memory Polymer (SMP). This choice has been made in order to take into account the mechanical state transitions of the SMP and its consequences on optical performances and properties of the photonic crystal.There are two main research challenges:The first challenge is to consider the complexity of nanoporous structure SMP in geometry, mechanical behavior and material properties. As already stated, nonlinearities, elastic instability and nanoscale effects contribute to increase the complexity.The second challenge refers to the development of a multi-physics (mechanical and optical) model and simulation of nanoporous SMP because of the novelty of this material.The objective of the research project is the mathematical representation of the mechanical and optical properties of the nanoporous crystal photonic SMP.The objective can be acquired by:- Development of a parametric and accurate geometrical models of native nanoporous structure;- Mechanical modelling of nanoporous crystal photonic SMP via FEA in order to obtain stress/strain status for three different situations (undeformed-native, deformed and recovered) managing structural non linearity in dependence of external loads, constrains, pore size and spatial distribution, material properties and residual stress/strain;- Development of optical models of the nanoporous photonic crystal SMP at the different states and predict the optical behaviors via geometrical optics simulation.- Coupling the mechanical state (deformation, stress-strain, nanoporous collapse etc.) with the optical properties (mainly reflection index) via multi physics modeling/simulation and different approaches (FEA modeling and geometrical optics) and data fusion.- Validation by experiments of the simulations performed on each model (mechanical, optical and multi-physic)

A modular, scalable and full-mesh bandwidth-upgradable optical interconnection between optoelectronic boards is guaranteed thanks to an optimized layout of standard MM fiber ribbons which divides the overall backplane into independent optical sub-circuits.

In this work an optical backplane prototype exploiting standard MM 12-fiber ribbons has proved a full-mesh optical connection between 8 boards, that is, each board provides bidirectional connections with each of the other boards. The optoelectronic boards are equipped with 8 pairs of MPO connectors, each pair (TX and RX) enclosed in a protective casing to ensure robustness during board insertion (Fig.1). The proposed technological solution, which relies on a patent-pending layout routing of optical connections, is modular. The optical backplane is in fact constituted by a frame, conform to ATCA standard structural specifications, divided into 8 subracks (one shown in Fig. 2) transversal to the 8 optoelectronic boards. The automated assembly of subracks, has been patented by CNR-ITIA [5]. The proposed layout thus offers the possibility of arbitrarily dividing the backplane into submodules for the use of different machines and allows easy maintenance of the backplane in case of breakage or replacement of optical connectors. Validation of the prototype was carried out with boards equipped with AVAGO miniPOD transceivers (12-MM-850nm-VCSEL arrays @10 Gb/s) to achieve 1Tb/s overall bandwidth. System characterizations demonstrated good performance with overall power loss due to fiber ribbon bending and insertion loss < 2 dB, eligible with 4.8 dB link power budget, and no penalty @ 10-12 BER with respect to back-to-back in each channel (Fig. 2). The advantages of the approach adopted in the design and implementation of this backplane are the automated assembly of off-the-shelf components (standard MM fiber ribbons) and a completely full-mesh bandwidth-upgradable optical interconnection. These features make this solution competitive for datacenters applications with respect to existing electrical backplane and even also to optical backplane based on tailored fiber ribbon sheets [3].

The rapid growth of ICT applications requires that data centers are now able to handle an ever increasing bandwidth capacity. Currently, the interconnections at data center level are managed through electrical backplane with copper connections. However electrical backplanes have now reached their limit in terms of transmission capacity and alternative optical solutions have recently been explored [1-3]. The main advantages offered by optical backplanes are: 1) no bandwidth limit; 2) reduction of backplane power dissipation [4]; 3) suppression of electromagnetic interference. Besides optical waveguides embedded in standard FR4 boards [1], which yet suffer from relatively high attenuation, optical fiber sheets have also been proposed as an easier solution to realize high-density and complex backplane [2]. However, this latter solution is not currently amenable to high-volume manufacturing processes.In this work an optical backplane prototype exploiting standard MM 12-fiber ribbons has proved a full-mesh optical connection between 8 boards, that is, each board provides bidirectional connections with each of the other boards.

A novel optical backplane relying on standard MM 12-fiber ribbons and MPO connectors is proposed for high-capacity ICT apparatus. A modular, scalable and full-mesh optical interconnection between optoelectronic boards is guaranteed thanks to an optimized fiber ribbon layout routing that divides the overall backplane into different and independent optical sub-circuits. The automated assembly of fiber ribbons into sub-circuits with a robotic work-cell is described. System validation of the optical backplane performed with commercial MM 12-fiber transceivers @10Gb/s proved the feasibility of the proposed solution for future optical interconnections with terabit overall capacity.

We present a cost-effective and highly-portable plastic prototype that can be interfaced with a cell phone to implement an optofluidic imaging cytometry platform. It is based on a PMMA microfluidic chip that fits inside an opto-mechanical platform fabricated by a 3D printer. The fluorescence excitation and imaging is performed using the LED and the CMOS from the cell phone increasing the compactness of the system. A custom developed application is used to analyze the images and provide a value of particle concentration.

This presentation reports the comparison of the machining performance of micro-EDM milling and sinking for the fabrication of micro-channels with controlled sloped walls realized in a hardened steel workpiece. The machining regime used for both micro-EDM sinking and milling is the fine-finishing. The results show that micro-EDM sinking is about 9 times faster than milling, though the effects of tool wear become relevant inducing a lack of accuracy in the final micro-features. Despite the slower machining time, micro-EDM milling provides a better control of the micro-channel dimensions and draft angles of the walls. No difference related to surface roughness is detected, since the energy level used in both approaches is the same. A micro-filter for hearing aid, dialysis media and inhaler, having a diameter of 2.3 mm characterized by a grid of 76 micro-pins, is machined in order to show the potential of the combination of both technologies

This paper reports the comparison of the machining performance of micro-EDM milling and sinking for the fabrication of micro-channels with controlled sloped walls realized in a hardened steel workpiece. The machining regime used for both micro-EDM sinking and milling is the fine-finishing. The results show that micro-EDM sinking is about 9 times faster than milling, though the effects of tool wear become relevant inducing a lack of accuracy in the final micro-features. Despite the slower machining time, micro-EDM milling provides a better control of the micro-channel dimensions and draft angles of the walls. No difference related to surface roughness is detected, since the energy level used in both approaches is the same. A micro-filter for hearing aid, dialysis media and inhaler, having a diameter of 2.3 mm characterized by a grid of 76 micro-pins, is machined in order to show the potential of the combination of both technologies.

The mechanical behaviour of specimens fabricated using FDM machine has been thoroughly studied and several works have been presented. However, they are focused on few materials, in particular ABS, while very few papers analysed the mechanical properties of FDM samples made by PLA filament. Even though ABS is well known for its superior mechanical properties, some applications might require materials with other properties, such as PLA.Therefore, a deeper investigation of the effect of the process on its properties is needed. In this study, at first, the influence of the main FDM process parameters, such as raster angle, extrusion width, air gap and extrusion temperature, on mechanical performance of PLA samples has been evaluated. The mechanical tests have been carried out on miniaturized tensile specimens focusing on the tensile test main properties: ultimate tensile stress, Young modulus and elongation at break. Moreover, an experimental campaign has been carried out on the effect of a thermal post-processing, in order to evaluate the effects of the treatment and its relation with the process parameters on the mechanical properties of the specimens.

In recent years, fused deposition modelling technology (FDM) has become one of the most important additive manufacturing technology due to its capability to produce functional prototypes with complex shape in a cost effectiveway. Recently, the trend towards miniaturization invested also this technology, since the request of micro-component israpidly growing due to the increasing number industrial sectors involved. Mechanical properties are fundamental in somesectors of high-quality micro-parts, so the knowledge of the influence of FDM process parameters on mechanical properties can be useful to extend its application and help the optimization of the parameter selection. In this context, theaim of this study is the analysis of the FDM capability and the room for improvement, through a comparison with a wellconsolidated industrial process, such as the micro-injection moulding. Although FDM quality cannot compete with thetechnologies industrially used for final products, its low cost and short time are very attractive for some applications.Moreover, the comparison can be interesting since FDM is often used to manufacture prototypes eventually made withmore performing industrial technologies, so that a measure of the quality and functionality of these prototypes can beextremely useful for product developers.

The wide investigation of the last decades on a variety of electronic products in order to increase their performance while miniaturizing them, has raised new issues related to their manufacturing, remanufacturing and reuse at their end-of-life. This scenario introduces further challenges, related to demanding specifications, to be addressed with enhanced or new (re-) manufacturing processes, innovative systems, and advanced strategies. In this context, this paper discusses some challenging applications exploiting novel automatic solutions on different complexity levels of the process, from the component to the whole system, including devices, tools and robotized work-cells developed by the authors.

In high-bandwidth ICT apparatus (data centers, servers, switching stations, etc.) and high-performance computing systems, high-effectiveness optical connections are requested. [2] These high-capacity ICT apparatus are based on optical backplanes where switching cards are connected each other with optical interconnection circuits. These optical interconnection circuits on the backplane allow signal transmission between cards. They should answer to several technical requirements as low optical power losses, low disturbance and interference in transmission, low size, standardized optical and mechanical interfaces, easy maintenance and, finally, low system costs. For these reasons, in the last years several solutions have been proposed for optical backplane interconnection circuits. The paper presents the design and development of a new optical backplane interconnection circuit for high-capacity ICT apparatus, mainly used for switching stations and distribution networks. It has several innovative aspects [1] and it solves drawbacks of prior art. The paper also shows circuit optical performances and describes the innovative assembly method conceived for the automatic assembly of optical backplane circuits.

Macroporous photonic crystals with optically bistable states have been fabricated by using thermoresponsive shape memory polymers. The reversible transition between an ordered permanent state and a disordered temporary state results in tremendous changes in the appearance and the optical properties of the membranes.

Macroporous photonic crystals with optically bistable states are fabricated by P. Jiang and co-workers using thermoresponsive shape memory polymers. On page 1509, the reversible transition between an ordered permanent state and a disordered temporary state during the shape memory "programming" and "recovery" processes results in tremendous changes in the appearance and optical properties of the photonic crystal membranes.

The demand for polymeric micro-components is increasing for applications in several industrial fields. Fused deposition modelling (FDM) is a consolidated rapid prototyping technology growing rapidly as industrial additive manufacturing technology due to its ability to build cheap and functional parts with complex geometry. In this study, several dog-bone miniaturized specimens in PLA were prepared by FDM and the relationships among the processing conditions and the mechanical properties were investigated. An ANOVA allowed to identify the influence of the FDM parameters on the part dimensional and geometrical accuracy. Since in micro FDM manufacturing the parameter setting is not sufficient to assure the final quality of the product, the part 3D solid model was modified to compensate both dimensional and geometrical errors. Finally, the miniaturized specimens were fabricated by micro-injection moulding (µIM) and their mechanical properties compared with those obtained using FDM.

The present study explores the design of an effective process chain that combines micro Abrasive Waterjet (micro-AWJ) and micro Wire Electro Discharge Machining (micro-WEDM) technologies. An experimental spring component is chosen as leading test case, since fine geometric features machining and low roughness on the cut walls are required. The advantages deriving from the two technologies combination are discussed in terms of machining time, surface roughness and feature accuracy. First, the performance of both processes are assessed by experimentation and discussed. Successively, different process chains are conceived for realizing two test cases with different size, displaying the advantages and drawbacks of the combinations.

This study reports unconventional, all-room-temperature shape memory (SM) effects using templated macroporous shape memory polymer (SMP) photonic crystals comprising a glassy copolymer with high-glass transition temperature. "Cold" programming of permanent periodic structures into temporary disordered configurations can be achieved by slowly evaporating various swelling solvents (e.g., ethanol) imbibed in the interconnecting macropores. The deformed macropores can be instantaneously recovered to the permanent geometry by exposing it to vapors and liquids of swelling solvents. By contrast, nonswelling solvents (e.g., hexane) cannot trigger "cold" programming and SM recovery. Extensive experimental and theoretical investigations reveal that the dynamics of swelling-induced plasticizing effects caused by fast diffusion of solvent molecules into the walls of macropores with nanoscopic thickness dominate both "cold" programming and recovery processes. Importantly, the striking color changes associated with the reversible SM transitions enable novel chromogenic sensors for selectively detecting trace amounts of swelling analytes mixed in nonswelling solvents. Using ethanol-hexane solutions as proof-of-concept mixtures, the ethanol detection limit of 150 ppm has been demonstrated. Besides reusable sensors, which can find important applications in environmental monitoring and petroleum process/product control, the programmable SMP photonic crystals possessing high mechanical strengths and all-room-temperature processability can provide vast opportunities in developing reconfigurable/rewritable nanooptical devices.

We have introduced a new hybrid fabrication method for lab-on-a-chip devices through the combination of femtosecond laser micromachining and removable insert micro-injection molding. This method is particularly suited for the fast prototyping of new devices, while maintaining a competitive low cost. To demonstrate the effectiveness of our approach, we designed, fabricated, and tested a completely integrated flow cytometer coupled to a portable media device. The system operation was tested with fluorescent plastic micro-bead solutions ranging from 100 beads/?L to 500 beads/?L. We demonstrated that this hybrid lab-on-a-chip fabrication technology is suitable for producing low-cost and portable biological microsystems and for effectively bridging the gap between new device concepts and their mass production.

Smart shape memory polymers can memorize and recover their permanent shape in response to an external stimulus (e.g., heat). They have been extensively exploited for a wide spectrum of applications ranging from biomedical devices to aerospace morphing structures. However, most of the existing shape memory polymers are thermoresponsive and their performance is hindered by heat-demanding programming and recovery steps. Although pressure is an easily adjustable process variable like temperature, pressureresponsive shape memory polymers are largely unexplored. Here, we report a series of shape memory polymers that enable unusual "cold" programming and instantaneousshape recovery triggered by applying a contact pressure at ambient conditions. Moreover, the interdisciplinary integration of scientific principles drawn from two disparate fields - the fast-growing photonic crystal and shape memory polymer technologies enables fabrication of reconfigurable photonic crystals, and simultaneously provides a simple and sensitive optical technique for investigating the intriguing shape memory effects at nanoscale.

Traditional shape memory polymers (SMPs) are mostly thermoresponsive and their applications in nanooptics are hindered by heat-demanding programming and recovery processes. By integrating a polyurethane-based shape memory copolymer with templating nanofabrication, reconfigurable/rewritable macroporous photonic crystals have been demonstrated. This SMP coupled with the unique macroporous structure enables unusual all-room-temperature shape memory cycles. "Cold" programming involving microscopic order-disorder transitions of the templated macropores is achieved by mechanically deforming the macroporous SMP membranes. The rapid recovery of the permanent, highly ordered photonic crystal structure from the temporary, disordered configuration can be triggered by multiple stimuli, including a large variety of vapors and solvents, heat, and microwave radiation. Importantly, the striking chromogenic effects associated with these athermal and thermal processes render a sensitive and noninvasive optical methodology for quantitatively characterizing the intriguing nanoscopic shape memory effects. Some critical parameters/mechanisms that could significantly affect the final performance of SMP-based reconfigurable photonic crystals, including strain recovery ratio, dynamics and reversibility of shape recovery, as well as capillary condensation of vapors in macropores, which plays a crucial role in vapor-triggered recovery, can be evaluated using this new optical technology.