The optoelectronic properties of photochromic materials change in response to exposure to certain wavelengths of light. These alterations arise from specific electronic reorganization of conjugation pathways due to photochemically-triggered cyclizations and conformational changes. Polymers with photochromic switches pendent to the backbone retain monomer-like optoelectronic photoswitching responses while incorporation of photochromic switches directly into a conjugated backbone allows for greater, and often more dramatic, influence on the polymer optoelectronic properties. This ability for light-controlled variation of optoelectronic properties has driven research in the field of main-chain photochromic conducting polymers, and recent developments in this area will be discussed.

The optical properties of mechanochromic materials change under mechanical stress. Segmented polyurethanes are elastomers composed of amorphous, saturated chain soft segments, and rigid pi-conjugated hard domains. Within aggregates of hard domains pi-pi interactions may form and result in perturbation of the optoelectronic properties of the system. Disruption and restoration of these electronic interactions within the material may lead to observable mechanochromic response. A series of oligothiophene diols and diamines, as well as a naphthalene diimide diol, have been synthesized for incorporation into the hard domains of segmented polyurethanes and polyureas using long poly(tetramethylene oxide) chains as soft segments. The resulting polymers were evaluated to determine their extent of polymerization and their thermal stability. The optical properties of the materials were studied in solution and as thin films. Where possible the electrochemical properties of the polymers were also explored. The length of the soft segment chains in the segmented polyurethanes hindered electronic coupling of hard domains. Future work involving smaller, more solubilizing soft segments may allow for easier material characterization and mechanochromic response. V

Improving the energy efficiency of residential rental properties has been a priority of Cornell Cooperative Extension of Tompkins County. However, traditional educational programming has had limited effectiveness due to a split incentive dynamic between landlords and tenants relative to property upgrades. We demonstrate that college students have broad interest in but limited knowledge of energy efficiency and are willing to pay a premium for relevant improvements. Our findings indicate that there is strong potential for Extension professionals to engage off-campus housing offices, students, and landlords in the development of modified leases and to facilitate educational programming that specifically addresses rental housing energy efficiency.

PurposeThe purpose of this paper is to explain the SEC staff's web site responses to a series of frequently asked questions concerning SEC Advisers Act Rule 206(4)‐5.Design/methodology/approachThe paper explains the SEC staff responses to FAQs on the ability to rely on prior Municipal Securities Rulemaking Board interpretations regarding MSRB Rules G‐37 and G‐38, determining who is an “official of a government entity,” determining who is a “covered associate,” payments of commissions or other compensation to brokers or others, the Rules' application to political action committees (PACs), and “effective dates” and “compliance dates” under the related recordkeeping rule.FindingsPay‐to‐play is the practice of making campaign contributions and related payments to elected officials in order to influence the awarding of lucrative contracts for the management of public pension plan assets and similar government investment accounts. The staff's answers to the FAQs announce cautious positions, do not address some of the more difficult issues advisers may face on a day‐to‐day basis, and are subject to change.Originality/valueThe paper provides practical guidance from experienced financial services lawyers.